Abstract 5130: Prognostic significance of loss of Cathepsin L expression in urinary bladder cancer progression

During 2021 there will be 83,730 new cases of urinary bladder cancer (UBC) in the US and 17,200 UBC deaths. Most UBC arise from the urothelial lining. UBC frequently recurs and is the most expensive cancer to treat due to the need for constant patient monitoring. New prognostic markers are needed to assist patient management. This study aims to determine if Cathepsin L is an independent prognostic factor after controlling for UBC Stage and Grade. We studied the interrelationship of Cathepsin L with Ki67, a prognostic marker in UBC. A clearer understanding of the biological mechanisms underlying UBC development and progression will lead to improved methods of UBC prognosis and suggest new therapies. Cathepsin L is a ubiquitously expressed cysteine endopeptidase capable of degrading enzymes, receptors, and transcription factors, and of activating enzymes, receptors, biologically active peptides, and pro-hormone processing by limited proteolysis. Subcellularly located in the endosomal lysosomal compartment, Cathepsin L is catalytically active at pH 3.0 - 6.5. This is a retrospective study of archived tissues and existing deidentified medical records and tumor registry information. Archived FFPE tissues were donated to Wood Hudson Cancer Research Laboratory by St. Elizabeth Healthcare (SEHC). The study was approved by the SEHC IRB. Tumors were from 41 women and 92 men. UBC were classified according to subtype, depth of invasion and grade by a Board Certified pathologist (LED). 36/62 (58.1%) of Stage 0 non-invasive UBC were Grade 1 or 2, and 26/62 (41.9%) were Grade 3 or 4. Similarly 39/90 papillary tumors (43.3%) were Grade 1 or 2 and 51/90 (36.7%) were Grade 3 or 4. In contrast 68/71 invasive UBC (Stages II, III and IV) were Grade 3 or 4. 39/90 papillary tumors were Grade 1 or 2. All non-papillary tumors were Grade 3 or 4. Ki 67 (clone MIB-1, Dako) and Cathepsin L (Abcam) expression were detected immunohistochemically. Cathepsin L was highly expressed in normal urothelium (p < 0.0001). In Stage 0, Cathepsin L expression in Grade 1,2,3 UBC was similar compared to expression in normal urothelium (p = 0.9070, 0.2560 and 0.0722). In Stage 0, Cathepsin L expression in Grade 4 UBC was significantly reduced compared to normal urothelium (p = 0.0011). Cathepsin L expression was significantly reduced in Grade 3 and 4 papillary tumors vs Grade 1 and 2 papillary tumors (p = 0.0002) and in Grade 3 and 4 non-papillary tumors vs Grade 3 and 4 papillary tumors (p = 0.0133). In each UBC subtype, grade or stage, when Cathepsin L expression was reduced cell proliferation as measured by Ki67 expression was increased and overall, this was significant (p < 0.0001). Significantly reduced Cathepsin L expression was associated with tumor recurrence and death from UBC (p = 0.03, p < 0.0001). These data suggest that when Cathepsin L is lost, intracellular levels of growth factor receptors such as EGFR may increase driving cell proliferation and UBC progression.

Citation Format: Julia H. Carter, James A. Deddens, Michelle C. Robillard, Mariah K. Dooley, Daniel Stelzer, Zachary S. Taylor, Larry E. Douglass. Prognostic significance of loss of Cathepsin L expression in urinary bladder cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5130.

Abstract 2267: Alterations in TGFβ signaling in ovarian cancer patients with TGFβ receptor 1 variants

Transforming growth factor β (TGFβ) signals through the TGFβ Receptor 1 (TGFβR1) and is implicated in many aspects of malignancy. TGFβR1 gene is frequently mutated in ovarian carcinomas (OvCa) (Chen, T., et al, Cancer Research 61, 4679-4682, 2001). Susceptibility to numerous cancers is linked to two germline variants of TGFβR1, a G to A single nucleotide polymorphism in intron 7 (Int 7G24A) and a nine base pair deletion in exon 1 (TGFβR1*6A) although the mechanism(s) for this association is still unclear. Since the canonical pathway for TGFβR1 signaling is via phosphorylation of SMAD, the goal was to determine the association of either or both variants with development of subtypes of OvCa and to measure phosphorylation of pSMAD in the epithelium and stroma of OvCas from women with either or both Int 7G24A and TGFβR1*6A. FFPE tissues from 122 women without a history of cancer, and 59 women with OvCa were obtained from St. Elizabeth Healthcare (N. KY) and from 63 women with OvCa through the Cooperative Human Tissue Network (Birmingham Ala). OvCa patients and non-cancer controls were age matched. St. Elizabeth Healthcare IRB gave permission for this study. Tumors were diagnosed in H&E stained histologic sections by a Board Certified Pathologist (LED) and were classified as either Low Malignant Potential (LMP), Type 1 (clear cell, mucinous and low grade serous and endometrioid) or Type 2 (high grade serous, high grade endometrioid, or carcinosarcoma). Variants were identified in extracted DNA from FFPE tissues using PCR, capillary electrophoresis (CE), RFLP, and SSCP. Histologic sections were stained by IHC using the DAKO LSAB2 kit (Agilent) and anti pSMAD 2 (Millipore AB3849-1). Stain was evaluated as cytoplasmic and nuclear Histoscores (stain Area X Intensity) by two observers (LED, JHC). Data were evaluated by “Gene Code” with Gene 1 wild type for both variants, Gene 2 homozygous or heterozygous for Int 7G24A, Gene 3 homozygous or heterozygous for TGFβR1*6A, and Gene 4 having both variants. Usual chi-tests were used to determine significance of contingency tables, ANOVA with multiple comparison adjusted were used for markers. KM plots and proportional hazards were used in survival tests. The frequency in Gene 1, 2, 3, and 4 was significantly different in controls vs. OvCa patients (p = 0.0010); 57.7% of OvCa patients had a TGFβR1 variant vs. 36.6% of controls. Frequency of TGFβR1 variants in 62 patients with Type 2 OvCa was 62.9%. Patient survival differed significantly between patients with LMP, Type 1, and Type 2 OvCa (p <0.0001). Differences in nuclear expression of pSMAD in both tumor epithelial and stromal cells between OvCa types were highly significant (p < 0.0001, p< 0.0092). pSMAD expression decreased significantly in the nuclei of both epithelial and stromal cells in Type 2 tumors. These data indicate that germline variations in the TGFβR1 gene are associated with high grade ovarian cancers and altered SMAD phosphorylation.

Citation Format: Julia H. Carter, James P. Schaeper, Taiping Chen, Diane W. Fritz, Leah Focke, Adrian Guy, James A. Deddens, Larry E. Douglass. Alterations in TGFβ signaling in ovarian cancer patients with TGFβ receptor 1 variants [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2267.

Abstract 747: Pak1, TGFα, Ki 67 and survival in human gastric and gastroesophageal junction adenocarcinomas

Stomach cancer is the third most common cause of cancer mortality worldwide. Most are adenocarcinomas. Adenocarcinomas of the stomach fall into two obvious groups based on site of origin; those arising in the area of the gastroesophageal junction (GEJ) and those arising from a more distal location, which we term gastric in this study. Adenocarcinomas of the stomach fall into four obvious groups based on a combination of genomic, molecular biologic, clinical and histopathologic characteristics (Nagara A, Kikuchi O, Bass AJ, Cancer Discovery 2019; DOI: 10.1158/2159-8290.CD-19-0487). We are reporting herein a study of 99 patients with adenocarcinoma of the stomach. This study evaluates the location of the tumor, the histopathologic features of the tumor, the immunohistochemically determined nuclear and cytoplasmic expression of P21 activated kinase (Pak 1), Transforming Growth Factor α (TGFα), and Ki67, a marker of cell proliferation. This study correlates these findings with patient survival. The study reveals:

1. significantly lower survival in patients with diffuse type adenocarcinoma compared to intestinal type, in both GEJ and gastric locations.

2. both GEJ and gastric adenocarcinomas had a poor prognosis.

3. increased expression of both TGFα and Pak1 in GEJ adenocarcinomas.

4. Ki67 expression is significantly less in diffuse type than the intestinal type (p=0.01 for GEJ and 0.03 for gastric).

5. cytoplasmic Pak1 and cytoplasmic TGFα were highly positively correlated (p=0.0001).

6. Ki67 expression was significantly inversely correlated with both nuclear Pak1 (p=0.04) and nuclear TGFα (p=0.02).

7. significantly increased expression of nuclear Pak1 in gastric diffuse type compared with gastric intestinal (p=0.0002) and GEJ intestinal (p=0.0001).

These data suggest that Pak1 and TGFα might serve as diagnostic biomarkers of subtypes of adenocarcinomas of the stomach and gastroesophogeal junction.

Citation Format: Larry E. Douglass, Michael Parritt, Adam Neltner, Mariah Dooley, Michelle Robillard, Molly Frydl, Leah Focke, Kyle Damen, James A. Deddens, Julia H. Carter. Pak1, TGFα, Ki 67 and survival in human gastric and gastroesophageal junction adenocarcinomas [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 747.

Transcription factors WT1 and p53 combined: a prognostic biomarker in ovarian cancer

Background

New approaches to ovarian cancer are needed to improve survival. Wilms’ tumour 1 (WT1) is a tumour-associated antigen expressed in many ovarian cancers. P53 is also often altered. The clinical significance of the combined expression of these two transcription factors has not been studied.

Methods

One hundred ninety-six ovarian tumours were classified histopathologically. Tumours were stained for WT1 and p53 immunohistochemically. Stains were analysed according to tumour type, grade and FIGO stage. Kaplan–Meier analyses on 96 invasive carcinomas determined whether categorical variables were related to survival.

Results

WT1 and p53 were related to ovarian tumour type, grade, FIGO stage and patient survival. Uniform nuclear p53 expression was associated with invasion and WT1 expression was associated with advanced grade, FIGO stage and poor survival. When WT1 and p53 were both in the age-adjusted Cox model, WT1 was significant while p53 was not. When we combined tumours expressing WT1 and p53, then adjusted for age and tumour subtype, the hazard ratio compared to tumours without WT1 and with normal p53 was 2.70; when adjusted for age and FIGO stage, the hazard ratio was 2.40.

Conclusions

WT1, an antigen target, is a biomarker for poor prognosis, particularly when combined with altered p53.

Abstract 2653: Cell proliferation and Cathepsin L expression are inversely correlated in bladder cancer progression and patient survival

In 2017 there will be an estimated 79,000 new cases of bladder cancer (UBC) resulting in 16,870 deaths. A better understanding of UBC progression and prognostic factors could improve patient management. UBC anatomic stage is determined by depth of invasion. Stage 0 is non-invasive, Stage 1 invades the sub-mucosa, Stage 2 invades the detrusor muscle, Stage 3 invades perivesical fat, and Stage 4 invades local or distant organs. 70-80% of UBCs are superficial, but can recur locally and be multifocal. Muscle invasive bladder cancers (MIBCs) can metastasize to pelvic lymph nodes or distant organs. To better understand the molecular mechanisms of UBC progression we measured cell proliferation utilizing the molecular marker of proliferating cells Ki 67 (Dako) and immunohistochemically detected expression of the lysosomal cysteine proteinase Cathepsin L (Abcam) in archived surgical specimens from 145 UBC patients. A board certified pathologist diagnosed and graded each histologic specimen and marked three areas for photography and image analysis. Clinical information and follow-up was obtained from existing medical records and the Kentucky Cancer Registry. IRB approval for the study was obtained from St. Elizabeth Healthcare who also donated the FFPE surgical specimens. We hypothesized that the % of proliferating tumor cells would increase with loss of cell differentiation and that Cathepsin L expression would increase with depth of tumor invasion into and beyond the detrusor muscle. Patients with high grade tumors (Grades 3 and 4) had a poor survival compared to patients with low grade tumors (p < 0.0001) and patients with MIBC (Stages 2-4) had a poorer survival that patients with superficial tumors (Stages 0 - 1) (p < 0.0001, HR = 18.63). Cell proliferation as determined by % of Ki 67 labeled nuclei was highly correlated with stage and grade (p <0.0001). In contrast Cathepsin L expression measured either semi-quantitatively by histoscore (area X intensity of stain) or quantitatively by computer assisted image analysis was negatively correlated with stage, grade, and Ki 67 labeling (p <0.0001). Recently multiple subtypes of MIBC have been identified, including basal tumors with squamous differentiation and luminal tumors. The highest rate of cell proliferation and the lowest expression of Cathepsin L in our data set were found in MIBC with squamous differentiation. Ki 67 labeling in UBC was highly prognostic of poor patient survival (p = 0.0003), whereas Cathepsin L expression as measured either by histoscore or image analysis was highly prognostic of good patient survival (p < 0.0001). Since Cathepsin L is encoded by the CTSL gene located on chromosome 9, these data are consistent with published reports of frequent genetic loss and mutations of chromosome 9 in UBC. These data also strongly support the value of UBC cell proliferation as a prognostic marker for stratifying UBC patients.

Citation Format: Larry E. Douglass, Michelle C. Robillard, Dan Stelzer, Mariah Dooley, James A. Deddens, Julia H. Carter. Cell proliferation and Cathepsin L expression are inversely correlated in bladder cancer progression and patient survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2653.

Abstract 2793: Evidence for WT1 as a potential target for immunotherapy of lethal ovarian cancer

Epithelial ovarian cancer is the leading cause of death from gynecologic cancers with 22,280 new cases anticipated in 2016 and 14,240 deaths. Most patients are diagnosed at late stages and have a poor prognosis. Radical surgery and chemotherapy are the primary treatment. When relapse occurs there are few treatment options. The overall survival rate of women with ovarian cancer is unchanged in 50 years. Approximately 70% of epithelial ovarian cancers are serous including low grade serous tumors, some of which may evolve from serous borderline tumors, and high grade serous carcinomas. The latter are thought to originate in the fallopian tube. There are eight other subtypes of invasive ovarian cancer. All invasive ovarian cancers have recently been classified into two subtypes, Type 1 (indolent) and Type 2 (aggressive). The Wilms’ Tumor 1 (WT1) protein is expressed in some normal tissues including the fallopian tube and ovary as well as in tumors such as ovarian and breast cancers and in leukemia. WT1 is a highly immunogenic tumor associated antigen. Mutated p53 is found in many high grade ovarian cancers. Recent reports indicate that WT1 and p53 may interact physically and functionally. Both WT1 and mutated p53 have been suggested as prognostic markers in ovarian cancer. We sought to determine the role of co-expression of mutated p53 and WT1 in overall survival of patients with ovarian cancer. Histologic sections were prepared from archived FFPE surgical specimens donated by St. Elizabeth Healthcare (Northern KY) and fully annotated by hospital records. H&E stained sections were diagnosed and graded by a board certified pathologist (LED) and included histologic sections from 41 borderline tumors and 98 Type 1 and Type 2 cancers. Adjacent sections were stained immunohistochemically using monoclonal antibodies (DAKO) to WT1 and p53. For survival analysis p53 was considered mutated if 75-100% of the tumor nuclei were stained (missense mutations) or if all nuclei were negative (truncated protein) and WT1 was considered either non-expressed (no stain) or expressed (some or all nuclei stained). While either mutated p53 or WT1 were prognostic alone of patient survival with Type 1 and Type 2 tumors, WT1 was a better predictor as seen by log-rank Chi-square. The 20 year survival probability of patients with tumors negative for both mutated p53 and WT1 was 70% and was significantly better than other patients (p < 0.0001). The 20 year survival probability for tumors negative for WT1 but expressing mutated p53 was 41%, and was 9% for tumors expressing WT1 and non-mutated p53. Patients with tumors expressing both WT1 and mutated p53 had a 20 year survival probability of 6%. Given these data and the immunogenicity of the WT1 tumor associated antigen we conclude that IHC detection of mutated p53 and WT1 in invasive ovarian cancers would be useful in stratifying patients eligible for immunologic approaches targeting WT1 for therapy of lethal ovarian cancers.

Citation Format: Julia H. Carter, James A. Deddens, Gretchen Mueller, Thomas G. Lewis, Mariah K. Dooley, Jackson O. Pemberton, Larry E. Douglass. Evidence for WT1 as a potential target for immunotherapy of lethal ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2793. doi:10.1158/1538-7445.AM2017-2793

Urinary Bisphenol A (BPA) Concentrations among Workers in Industries that Manufacture and Use BPA in the USA

Background

Bisphenol A (BPA) toxicity and exposure risk to humans has been the subject of considerable scientific debate; however, published occupational exposure data for BPA are limited.

Methods

In 2013-2014, 77 workers at six US companies making BPA, BPA-based resins, or BPA-filled wax provided seven urine samples over two consecutive work days (151 worker-days, 525 samples). Participant information included industry, job, tasks, personal protective equipment used, hygiene behaviors, and canned food/beverage consumption. Total (free plus conjugated) BPA, quantified in urine by mass spectrometry, was detected in all samples.

Results

The geometric mean (GM) creatinine-adjusted total BPA (total BPACR) concentration was 88.0 µg g-1 (range 0.78-18900 µg g-1), ~70 times higher than in US adults in 2013-2014 (1.27 µg g-1). GM total BPACR increased during Day 1 (26.6-127 µg g-1), decreased by pre-shift Day 2 (84.4 µg g-1) then increased during Day 2 to 178 µg g-1. By industry, baseline and post-baseline total BPACR was highest in BPA-filled wax manufacturing/reclaim (GM = 111 µg g-1) and lowest in phenolic resin manufacturing (GM = 6.56 µg g-1). By job, total BPACR was highest at baseline in maintenance workers (GM = 157 µg g-1) and post-baseline in those working with molten BPA-filled wax (GM = 441 µg g-1). Workers in the job of flaking a BPA-based resin had the lowest concentrations at baseline (GM = 4.81 µg g-1) and post-baseline (GM = 23.2 µg g-1). In multiple regression models, at baseline, industry significantly predicted increased total BPACR (P = 0.0248); post-baseline, handling BPA containers (P = 0.0035), taking ≥3 process/bulk samples with BPA (P = 0.0002) and wearing a Tyvek® coverall (P = 0.0042) significantly predicted increased total BPACR (after adjusting for total BPACR at baseline, time point, and body mass index).

Conclusion

Several work-related factors, including industry, job, and certain tasks performed, were associated with increased urinary total BPACR concentrations in this group of manufacturing workers. The potential for BPA-related health effects among these workers is unknown.

Abstract 3919: Phosphorylation of eIF4E is a critical factor in development and progression of breast cancer in women

Breast cancer survival rates vary according to stage, tumor grade, and receptor status. While some cancer patients respond well to targeted therapy many patients respond poorly. Critical for advancing new therapies is developing a better understanding of the molecular drivers of breast cancer tumorigenesis and malignant progression. The synthesis of new proteins (translation) is important for cancer cell survival, growth, and proliferation. eIF4E is a rate limiting step in translation. Targeting translation has been suggested as a novel strategy for therapy of malignancies originating in the epithelium since eIF4E regulates the translation of multiple malignancy associated mRNAs. eIF4E is activated by phosphorylation downstream of the Mnk 1 and 2 kinases. We hypothesized that phosphorylation of eIF4E plays a critical role in driving breast cancer and is elevated in advanced cancers and metastases. Using immunochemistry and semi-quantitative cellular pathology approaches we analyzed expression of eIF4E and phospho-eIF4E in 168 FFPE archived surgical specimens of normal breast, benign breast disease and pre-invasive, invasive, and metastatic breast cancer. Immunohistochemical stain in the cytoplasm and nuclei of breast epithelial cells was evaluated microscopically by the area of epithelium stained and the intensity of stain (Histoscore = Area X Intensity). We found that expression of eIF4E in the cytoplasm and nuclei of breast epithelial cells was highly correlated with tumor progression (p < 0.0001 and p = 0.0025, respectively). Similarly phospho-eIF4E expression increased in concert with tumor progression (p < 0.0001) in both the cytoplasm and nuclei of breast epithelial cells. Interestingly, while expression of both eIF4E and phospho-eIF4E was not significantly increased in benign breast disease, expression of both eIF4E and phospho-eIF4E was significantly increased in atypical duct hyperplasia (p = 0.01) and in carcinoma in situ (p < 0.0001) as well as in invasive ductal carcinoma (p < 0.0001) relative to normal duct epithelium. Expression of eIF4E and phospho-eIF4E was also increased in lobular carcinoma in situ relative to expression in normal lobules. Breast cancers of all receptor types (ER+/-, PR +/-, Her2+/-, and triple negative) had increased expression of eIF4E and phospho-eIF4E relative to normal duct epithelium. These data are consistent with the conclusion that eIF4E and phospho-eIF4E are critical factors in breast cancer development and progression and that targeting either eIF4E or phosphorylation of eIF4E may be an effective strategy for therapy of all subtypes of breast cancer.

Citation Format: Chad A. Dumstorf, Larry E. Douglass, James A. Deddens, Thomas G. Lewis, Kyle Darpel, Christian Gausvik, Jeremy R. Graff, Julia H. Carter. Phosphorylation of eIF4E is a critical factor in development and progression of breast cancer in women. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3919.

Birth defects in infants born to employees of a microelectronics and business machine manufacturing facility

BACKGROUND

Concerns about solvent releases from a microelectronics/business machine manufacturing facility in upstate New York led to interest in the health of former workers, including this investigation of birth defects in children of male and female employees.

METHODS

Children born 1983 to 2001 to facility employees were enumerated and matched to New York State's Congenital Malformations Registry. Reported structural birth defects were compared with numbers expected from state rates (excluding New York City), generating standardized prevalence ratios (SPRs). Exposure assessors classified employees as ever/never potentially exposed at the facility to metals, chlorinated hydrocarbons, and other hydrocarbons during windows critical to organogenesis (female workers) or spermatogenesis (male workers). Among workers, adjusted prevalence ratios were generated to evaluate associations between potential exposures and specific birth defects.

RESULTS

External comparisons for structural defects were at expectation for infants of male workers (SPR = 1.01; 95% confidence interval [CI], 0.77-1.29; n = 60) and lower for births to female workers (SPR = 0.84; 95% CI, 0.50-1.33; n = 18). Among full-term infants of male workers, ventricular septal defects (VSDs) were somewhat elevated compared with the general population (SPR = 1.58; 95% CI, 0.99-2.39; n = 22). Within the cohort, potential paternal metal exposure was associated with increased VSD risk (adjusted prevalence ratio = 2.70; 95% CI, = 1.09-6.67; n = 7).

CONCLUSION

While overall SPRs were near expectation, paternal exposure to metals (primarily lead) appeared to be associated with increased VSD risk in infants. Take-home of occupational exposures, nonoccupational exposures, and chance could not be ruled out as causes. Case numbers for many defects were small, limiting assessment of the role of occupational exposures. Birth Defects Research (Part A) 106:696-707, 2016. © 2016 Wiley Periodicals, Inc.

Phosphorylation of eIF4E serine 209 is associated with tumour progression and reduced survival in malignant melanoma

Background:

Melanoma is a disease that primarily arises in the skin but is a derivative of the neural crest. Eukaryotic translation initiation factor 4E (eIF4E) regulates translation of multiple malignancy-associated mRNAs and is overexpressed in many epithelial tumours. However, expression in human tumours derived from the neural crest is unknown. Here, we determined the association of eIF4E and phospho-eIF4E expression in melanocytic lesions with malignant conversion, metastatic potential and patient survival.

Methods:

Archived formalin-fixed, paraffin-embedded surgical specimens from 114 patients with melanocytic lesions were stained immunohistochemically for eIF4E and phospho-eIF4E and evaluated semiquantitatively. The relationship between cytoplasmic and nuclear eIF4E and phospho-eIF4E protein expression, melanocytic lesion subtype and tumour progression was determined. Kaplan–Meier survival analyses and Cox proportional hazard regression were performed.

Results:

Increased eIF4E and phospho-eIF4E expression was highly associated with malignancy (P<0.0001). High nuclear phospho-eIF4E was associated with synchronous or future metastasis (P=0.0059). Kaplan–Meier analyses demonstrated highly significant associations between high histoscores for cytoplasmic and nuclear phospho-eIF4E and reduced survival in all patients (P=0.0003 and 0.0009, respectively).

Conclusions:

Increased melanoma expression of eIF4E and phospho-eIF4E is associated with metastatic potential, reduced survival and increased risk of death.

Abstract A28: Eukaryotic initiation factor 4E phosphorylation in human malignant melanoma

Malignant melanoma continues to be a challenge both in terms of understanding the biologic mechanisms behind its behavior, as well as applying that information toward developing new therapeutic interventions. From 1992 through 2006, the incidence of malignant melanoma increased annually in the United States among non-Hispanic whites in all age groups, with death rates increased in patients 65 years and older. Approximately 70,000 new cases of invasive melanoma are anticipated in 2014. The need for better therapeutic strategies to combat these alarming statistics is paramount. While melanoma is a disease that primarily arises in the skin, it is a derivative of neural crest. During embryogenesis, an epithelial to mesenchymal transition occurs in order to form these cells. Once formed, these neural crest cells migrate to various locations in the body and differentiate into cells of the central and peripheral nervous system, medullary cells of the adrenal glands, various craniofacial connective tissues, and melanocytes. The histopathologic progression in melanocytic transformation is described by Chin, et al., (1998) as follows: (1) Normal skin has an even distribution of dendritic melanocytes throughout the basal layer; (2) Benign proliferation of melanocytes - in a nevus, nevoid melanocytes are organized into uniform nests of cells; (3) Melanocyte dysplasia - a dysplastic nevus has irregular and bridging nests of cells consisting of large atypical melanocytes; (4) In-situ melanoma, radial growth phase (RGP) - single dysplastic cells are present in the epidermis (Pagetoid spread); (5) Malignant melanoma, the vertical growth phase (VGP). Breslow thickness, the thickness of the melanoma from the most superficial nucleated layer, the granular layer, to the deepest level of invasion, has a strong predictive value in the prognosis of patients with non-metastatic melanomas. In our present study of 75 FFPE archived surgical specimens from 52 melanoma patients, we examined immunohistochemically detected cytoplasmic and nuclear expression of eukaryotic translation initiation factor 4E (eIF4E) and phosphorylated eIF4E in the four major subtypes of cutaneous melanoma (superficial spreading melanoma, nodular melanoma, lentigo maligna melanoma and acral lentiginous melanoma), as well as in benign nevi, in relation to clinical outcome. Although the importance of activation of eIF4E through phosphorylation for cell proliferation and transformation in cultured cells and animal models of epithelial derived carcinomas has been documented, the role of eIF4E phosphorylation in transformation and histopathologic progression of melanocytes to melanomas has not previously been reported. We find that both eIF4E and phosphorylated eIF4E are increased in all major subtypes of human cutaneous malignant melanomas relative to benign dermal nevi. Importantly, in a subset of these specimens, nuclear phosphorylated eIF4E is significantly increased in nodular and metastatic melanomas compared to superficial spreading melanomas (P = 0.02). Survival analyses indicate that increased nuclear phosphorylated eIF4E is significantly associated with reduced survival (P = 0.0019, 3.994 Hazard Ratio). Since it has recently been reported (Konicek, et al., 2011) that inhibition of eIF4E phosphorylation with an orally bioavailable inhibitor of MAPK-interacting kinases (MNK) reduces lung metastases in the B16 mouse melanoma model, the present data may point to a novel cancer therapeutic strategy for treatment of human malignant melanoma, namely inhibition of eIF4E phosphorylation.

Citation Format: Julia H. Carter, Reed Spaulding, James A. Deddens, Bruce M. Colligan, Grant Lewis, Jackson O. Pemberton, Jeremy R. Graff, Larry E. Douglass. Eukaryotic initiation factor 4E phosphorylation in human malignant melanoma. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Melanoma: From Biology to Therapy; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(14 Suppl):Abstract nr A28.

A case study of a recent decline in the dialysis fatality rate

Geoffrey Berlyne, whom we honor in this Festschrift, has contributed much to the modern understanding of diseases of the kidney, and of the clinical and metabolic disorders that occur in acute and chronic renal failure. The Festschrift highlights the many areas of his contributions. It is important to note that underlying them all is astute clinical observation, incisive analysis and reasoning, a breadth of approach, experimentation that facilitated understanding of the relevant clinical issues, and an unusual clarity of exposition in the literature. As author, editor, and teacher, Geoffrey Berlyne has brought this clarity of approach to a generation in nephrology. The following analysis of clinical data from a working dialysis unit, rendering care to a predominantly underprivileged patient population, is presented in the hope that it throws light on everyday problems in nephrology in a manner similar to that in which Geoffrey has guided the nephrology community.

Carbon Nanotube and Nanofiber Exposure Assessments: An Analysis of 14 Site Visits

Recent evidence has suggested the potential for wide-ranging health effects that could result from exposure to carbon nanotubes (CNT) and carbon nanofibers (CNF). In response, the National Institute for Occupational Safety and Health (NIOSH) set a recommended exposure limit (REL) for CNT and CNF: 1 µg m(-3) as an 8-h time weighted average (TWA) of elemental carbon (EC) for the respirable size fraction. The purpose of this study was to conduct an industrywide exposure assessment among US CNT and CNF manufacturers and users. Fourteen total sites were visited to assess exposures to CNT (13 sites) and CNF (1 site). Personal breathing zone (PBZ) and area samples were collected for both the inhalable and respirable mass concentration of EC, using NIOSH Method 5040. Inhalable PBZ samples were collected at nine sites while at the remaining five sites both respirable and inhalable PBZ samples were collected side-by-side. Transmission electron microscopy (TEM) PBZ and area samples were also collected at the inhalable size fraction and analyzed to quantify and size CNT and CNF agglomerate and fibrous exposures. Respirable EC PBZ concentrations ranged from 0.02 to 2.94 µg m(-3) with a geometric mean (GM) of 0.34 µg m(-3) and an 8-h TWA of 0.16 µg m(-3). PBZ samples at the inhalable size fraction for EC ranged from 0.01 to 79.57 µg m(-3) with a GM of 1.21 µg m(-3). PBZ samples analyzed by TEM showed concentrations ranging from 0.0001 to 1.613 CNT or CNF-structures per cm(3) with a GM of 0.008 and an 8-h TWA concentration of 0.003. The most common CNT structure sizes were found to be larger agglomerates in the 2-5 µm range as well as agglomerates >5 µm. A statistically significant correlation was observed between the inhalable samples for the mass of EC and structure counts by TEM (Spearman ρ = 0.39, P < 0.0001). Overall, EC PBZ and area TWA samples were below the NIOSH REL (96% were <1 μg m(-3) at the respirable size fraction), while 30% of the inhalable PBZ EC samples were found to be >1 μg m(-3). Until more information is known about health effects associated with larger agglomerates, it seems prudent to assess worker exposure to airborne CNT and CNF materials by monitoring EC at both the respirable and inhalable size fractions. Concurrent TEM samples should be collected to confirm the presence of CNT and CNF.

Trends in worker hearing loss by industry sector, 1981-2010

BACKGROUND

The purpose of this study was to estimate the incidence and prevalence of hearing loss for noise-exposed U.S. workers by industry sector and 5-year time period, covering 30 years.

METHODS

Audiograms for 1.8 million workers from 1981-2010 were examined. Incidence and prevalence were estimated by industry sector and time period. The adjusted risk of incident hearing loss within each time period and industry sector as compared with a reference time period was also estimated.

RESULTS

The adjusted risk for incident hearing loss decreased over time when all industry sectors were combined. However, the risk remained high for workers in Healthcare and Social Assistance, and the prevalence was consistently high for Mining and Construction workers.

CONCLUSIONS

While progress has been made in reducing the risk of incident hearing loss within most industry sectors, additional efforts are needed within Mining, Construction and Healthcare and Social Assistance.

Mortality among a cohort of U.S. commercial airline cockpit crew

BACKGROUND

We evaluated mortality among 5,964 former U.S. commercial cockpit crew (pilots and flight engineers). The outcomes of a priori interest were non-chronic lymphocytic leukemia, central nervous system (CNS) cancer (including brain), and malignant melanoma.

METHODS

Vital status was ascertained through 2008. Life table and Cox regression analyses were conducted. Cumulative exposure to cosmic radiation was estimated from work history data.

RESULTS

Compared to the U.S. general population, mortality from all causes, all cancer, and cardiovascular diseases was decreased, but mortality from aircraft accidents was highly elevated. Mortality was elevated for malignant melanoma but not for non-chronic lymphocytic leukemia. CNS cancer mortality increased with an increase in cumulative radiation dose.

CONCLUSIONS

Cockpit crew had a low all-cause, all-cancer, and cardiovascular disease mortality but elevated aircraft accident mortality. Further studies are needed to clarify the risk of CNS and other radiation-associated cancers in relation to cosmic radiation and other workplace exposures.

Prevalence of workers with shifts in hearing by industry: a comparison of OSHA and NIOSH Hearing Shift Criteria

OBJECTIVE

The purpose of this study was to compare the prevalence of workers with National Institute for Occupational Safety and Health significant threshold shifts (NSTS), Occupational Safety and Health Administration standard threshold shifts (OSTS), and with OSTS with age correction (OSTS-A), by industry using North American Industry Classification System codes.

METHODS

From 2001 to 2010, worker audiograms were examined. Prevalence and adjusted prevalence ratios for NSTS were estimated by industry. NSTS, OSTS, and OSTS-A prevalences were compared by industry.

RESULTS

Twenty percent of workers had an NSTS, 14% had an OSTS, and 6% had an OSTS-A. For most industries, the OSTS and OSTS-A criteria identified 28% to 36% and 66% to 74% fewer workers than the NSTS criteria, respectively.

CONCLUSIONS

Use of NSTS criteria allowing for earlier detection of shifts in hearing is recommended for improved prevention of occupational hearing loss.

Carbon nanotube dosimetry: from workplace exposure assessment to inhalation toxicology

Background

Dosimetry for toxicology studies involving carbon nanotubes (CNT) is challenging because of a lack of detailed occupational exposure assessments. Therefore, exposure assessment findings, measuring the mass concentration of elemental carbon from personal breathing zone (PBZ) samples, from 8 U.S.-based multi-walled CNT (MWCNT) manufacturers and users were extrapolated to results of an inhalation study in mice.

Results

Upon analysis, an inhalable elemental carbon mass concentration arithmetic mean of 10.6 μg/m³ (geometric mean 4.21 μg/m³) was found among workers exposed to MWCNT. The concentration equates to a deposited dose of approximately 4.07 μg/d in a human, equivalent to 2 ng/d in the mouse. For MWCNT inhalation, mice were exposed for 19 d with daily depositions of 1970 ng (equivalent to 1000 d of a human exposure; cumulative 76 yr), 197 ng (100 d; 7.6 yr), and 19.7 ng (10 d; 0.76 yr) and harvested at 0, 3, 28, and 84 d post-exposure to assess pulmonary toxicity. The high dose showed cytotoxicity and inflammation that persisted through 84 d after exposure. The middle dose had no polymorphonuclear cell influx with transient cytotoxicity. The low dose was associated with a low grade inflammatory response measured by changes in mRNA expression. Increased inflammatory proteins were present in the lavage fluid at the high and middle dose through 28 d post-exposure. Pathology, including epithelial hyperplasia and peribronchiolar inflammation, was only noted at the high dose.

Conclusion

These findings showed a limited pulmonary inflammatory potential of MWCNT at levels corresponding to the average inhalable elemental carbon concentrations observed in U.S.-based CNT facilities and estimates suggest considerable years of exposure are necessary for significant pathology to occur at that level.

Laparoscopic oviductal artificial insemination improves pregnancy success in exogenous gonadotropin-treated domestic cats as a model for endangered felids

Artificial insemination (AI) in cats traditionally uses equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) to induce follicular development and ovulation, with subsequent bilateral laparoscopic intrauterine insemination. However, long-acting hCG generates undesirable secondary ovulations in cats. Uterine AI also requires relatively high numbers of spermatozoa for fertilization (~8 × 10(6) sperm), and unfortunately, sperm recovery from felids is frequently poor. Using short-acting porcine luteinizing hormone (pLH) instead of hCG, and using the oviduct as the site of sperm deposition, could improve fertilization success while requiring fewer spermatozoa. Our objectives were to compare pregnancy and fertilization success between 1) uterine and oviductal inseminations and 2) eCG/hCG and eCG/pLH regimens in domestic cats. Sixteen females received either eCG (100 IU)/hCG (75 IU) or eCG (100 IU)/pLH (1000 IU). All females ovulated and were inseminated in one uterine horn and the contralateral oviduct using fresh semen (1 × 10(6) motile sperm/site) from a different male for each site. Pregnant females (11/16; 69%) were spayed approximately 20 days post-AI, and fetal paternity was genetically determined. The number of corpora lutea (CL) at AI was similar between hormone regimens, but hCG increased the number of CL at 20 days post-AI. Numbers of pregnancies and normal fetuses were similar between regimens. Implantation abnormalities were observed in the hCG group only. Finally, oviductal AI produced more fetuses than uterine AI. In summary, laparoscopic oviductal AI with low sperm numbers in eCG/hCG- or eCG/pLH-treated females resulted in high pregnancy and fertilization percentages in domestic cats. Our subsequent successes with oviductal AI in eCG/pLH-treated nondomestic felids to produce healthy offspring supports cross-species applicability.

A prospective study of carpal tunnel syndrome: workplace and individual risk factors

OBJECTIVES

To quantify the risk for carpal tunnel syndrome (CTS) from workplace physical factors, particularly hand activity level and forceful exertion, while taking into account individual factors including age, gender, body mass index (BMI), and pre-existing medical conditions.

METHODS

Three healthcare and manufacturing workplaces were selected for inclusion on the basis of range of exposure to hand activity level and forceful exertion represented by their jobs. Each study participant's job tasks were observed and evaluated onsite and videotaped for further analysis, including frequency and duration of exertion and postural deviation. Individual health assessment entailed electrodiagnostic testing of median and ulnar nerves, physical examination and questionnaires at baseline with annual follow-up for 2 years.

RESULTS

The incidence of dominant hand CTS during the study was 5.11 per 100 person-years (29 cases). Adjusted HRs for dominant hand CTS were as follows: working with forceful exertion ≥ 20% but <60% of the time: 2.83 (1.18, 6.79) and ≥ 60% of the time vs <20%: 19.57 (5.96, 64.24), BMI ≥ 30 kg/m(2) (obesity): 3.19 (1.28, 7.98). The American Conference for Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) for hand activity level also predicted CTS, HR=1.40 (1.11, 1.78) for each unit increase in the TLV ratio, controlling for obesity and job strain.

CONCLUSIONS

Workplace and individual risk factors both contribute to the risk for CTS. Time spent in forceful exertion can be a greater risk for CTS than obesity if the job exposure is high. Preventive workplace efforts should target forceful exertions.

Prevalence of hearing loss in the United States by industry

BACKGROUND

Twenty-two million workers are exposed to hazardous noise in the United States. The purpose of this study is to estimate the prevalence of hearing loss among U.S. industries.

METHODS

We examined 2000-2008 audiograms for male and female workers ages 18-65, who had higher occupational noise exposures than the general population. Prevalence and adjusted prevalence ratios (PRs) for hearing loss were estimated and compared across industries.

RESULTS

In our sample, 18% of workers had hearing loss. When compared with the Couriers and Messengers industry sub-sector, workers employed in Mining (PR = 1.65, CI = 1.57-1.73), Wood Product Manufacturing (PR = 1.65, CL = 1.61-1.70), Construction of Buildings (PR = 1.52, CI = 1.45-1.59), and Real Estate and Rental and Leasing (PR = 1.61, CL = 1.51-1.71) [corrected] had higher risks for hearing loss.

CONCLUSIONS

Workers in the Mining, Manufacturing, and Construction industries need better engineering controls for noise and stronger hearing conservation strategies. More hearing loss research is also needed within traditional "low-risk" industries like Real Estate.

Abstract 22: Overexpression of PAK 1 is a favorable prognostic biomarker in malignant melanoma

The incidence of malignant melanoma, the most lethal form of skin cancer, is increasing. Approximately 76,000 new cases of invasive melanoma and 9,000 deaths from the disease are anticipated in 2012. Melanoma, a heterogeneous and multistep disease, is one of the most frequent cancers in young adults 20-30 years of age. Identification of prognostic factors for melanoma patients and a better understanding of melanoma progression are needed. An initial radial growth phase of melanomas is followed by a vertical growth phase. Although metastatic capacity is thought to be acquired during the vertical growth phase, metastases occur in some patients with primary melanomas having a radial growth pattern. In this study of 40 melanoma patients we examined immunohistochemically detected cytoplasmic and nuclear expression of p21-activated kinase 1 (PAK 1) in FFPE archived surgical specimens of the four major subtypes of cutaneous melanoma (superficial spreading melanoma, nodular melanoma, lentigo maligna melanoma, and acral lentiginous melanoma), as well as benign nevi and normal skin, in relation to clinical outcome. The highest expression of both nuclear and cytoplasmic PAK 1 was found in superficial spreading melanomas (which comprise 70% of melanoma cases in the US) and was significantly increased relative to normal skin (P &lt; 0.0001). High nuclear and cytoplasmic expression of PAK 1 relative to normal skin was found in some (8-17%) of the other forms of melanoma. Overexpression of PAK 1 was not found in lymph node or lung metastases from 13 patients. Overexpression of cytoplasmic PAK 1 in the primary tumors from 28 patients was associated with increased survival (P = 0.03). Only 25% of patients with uniformly high (3+) cytoplasmic expression of PAK 1 in their primary tumor died compared to 67% of patients with less cytoplasmic PAK 1. Similarly only 22% of patients with more than trace expression of PAK 1 in 50% of the nuclei in their primary tumor died compared to 61% of patients with less nuclear PAK 1. The difference in survival between 28 patients with high and low nuclear PAK 1 in their primary tumor approached significance (P = 0.062). Overall, patients with superficial spreading melanoma had not only the highest cytoplasmic and nuclear PAK 1 expression in their tumor, but also tended to have better survival than patients with other forms of melanoma (P = 0.07). PAK 1 has multiple cellular effects including effects on growth factor signaling, cytoskeletal signaling, oncogenic transformation and survival, and chromatin and nuclear signaling. Our data indicate that PAK 1 overexpression in primary melanomas portends increased survival for the melanoma patient, possibly reflecting the relevance of PAK 1 to the radial vs. the vertical phase of melanoma progression.

Citation Format: Julia H. Carter, Nelson R. Spaulding, Bruce M. Colligan, James A. Deddens, Larry E. Douglass. Overexpression of PAK 1 is a favorable prognostic biomarker in malignant melanoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 22. doi:10.1158/1538-7445.AM2013-22

Use of and occupational exposure to indium in the United States

Indium use has increased greatly in the past decade in parallel with the growth of flat-panel displays, touchscreens, optoelectronic devices, and photovoltaic cells. Much of this growth has been in the use of indium tin oxide (ITO). This increased use has resulted in more frequent and intense exposure of workers to indium. Starting with case reports and followed by epidemiological studies, exposure to ITO has been linked to serious and sometimes fatal lung disease in workers. Much of this research was conducted in facilities that process sintered ITO, including manufacture, grinding, and indium reclamation from waste material. Little has been known about indium exposure to workers in downstream applications. In 2009-2011, the National Institute for Occupational Safety and Health (NIOSH) contacted 89 potential indium-using companies; 65 (73%) responded, and 43 of the 65 responders used an indium material. Our objective was to identify current workplace applications of indium materials, tasks with potential indium exposure, and exposure controls being used. Air sampling for indium was either conducted by NIOSH or companies provided their data for a total of 63 air samples (41 personal, 22 area) across 10 companies. Indium exposure exceeded the NIOSH recommended exposure limit (REL) of 0.1 mg/m(3) for certain methods of resurfacing ITO sputter targets, cleaning sputter chamber interiors, and in manufacturing some inorganic indium compounds. Indium air concentrations were low in sputter target bonding with indium solder, backside thinning and polishing of fabricated indium phosphide-based semiconductor devices, metal alloy production, and in making indium-based solder pastes. Exposure controls such as containment, local exhaust ventilation (LEV), and tool-mounted LEV can be effective at reducing exposure. In conclusion, occupational hygienists should be aware that the manufacture and use of indium materials can result in indium air concentrations that exceed the NIOSH REL. Given recent findings of adverse health effects in workers, research is needed to determine if the current REL sufficiently protects workers against indium-related diseases.

Occupational exposure assessment in carbon nanotube and nanofiber primary and secondary manufacturers: mobile direct-reading sampling

RESEARCH SIGNIFICANCE: Toxicological evidence suggests the potential for a wide range of health effects from exposure to carbon nanotubes (CNTs) and carbon nanofibers (CNFs). To date, there has been much focus on the use of direct-reading instruments (DRIs) to assess multiple airborne exposure metrics for potential exposures to CNTs and CNFs due to their ease of use and ability to provide instantaneous results. Still, uncertainty exists in the usefulness and interpretation of the data. To address this gap, air-monitoring was conducted at six sites identified as CNT and CNF manufacturers or users and results were compared with filter-based metrics.

METHODS

Particle number, respirable mass, and active surface area concentrations were monitored with a condensation particle counter, a photometer, and a diffusion charger, respectively. The instruments were placed on a mobile cart and used as area monitors in parallel with filter-based elemental carbon (EC) and electron microscopy samples. Repeat samples were collected on consecutive days, when possible, during the same processes. All instruments in this study are portable and routinely used for industrial hygiene sampling.

RESULTS

Differences were not observed among the various sampled processes compared with concurrent indoor or outdoor background samples while examining the different DRI exposure metrics. Such data were also inconsistent with results for filter-based samples collected concurrently at the same sites [Dahm MM, Evans DE, Schubauer-Berigan MK et al. (2012) Occupational exposure assessment in CNT and nanofiber primary and secondary manufacturers. Ann Occup Hyg; 56: 542-56]. Significant variability was seen between these processes as well as the indoor and outdoor backgrounds. However, no clear pattern emerged linking the DRI results to the EC or the microscopy data (CNT and CNF structure counts).

CONCLUSIONS

Overall, no consistent trends were seen among similar processes at the various sites. The DRI instruments employed were limited in their usefulness in assessing and quantifying potential exposures at the sampled sites but were helpful for hypothesis generation, control technology evaluations, and other air quality issues. The DRIs employed are nonspecific, aerosol monitors, and, therefore, subject to interferences. As such, it is necessary to collect samples for analysis by more selective, time-integrated, laboratory-based methods to confirm and quantify exposures.

Occupational exposure to diisononyl phthalate (DiNP) in polyvinyl chloride processing operations

PURPOSE

Diisononyl phthalate (DiNP) is primarily used as a plasticizer in polyvinyl chloride (PVC) materials. While information is available on general population exposure to DiNP, occupational exposure data are lacking. We present DiNP metabolite urinary concentrations in PVC processing workers, estimate DiNP daily intake for these workers, and compare worker estimates to other populations.

METHODS

We assessed DiNP exposure in participants from two companies that manufactured PVC materials, a PVC film manufacturer (n = 25) and a PVC custom compounder (n = 12). A mid-shift and end-shift urine sample was collected from each participant and analyzed for the DiNP metabolite mono(carboxy-isooctyl) phthalate (MCiOP). Mixed models were used to assess the effect on MCiOP concentrations of a worker being assigned to (1) a task using DiNP and (2) a shift where DiNP was used. A simple pharmacokinetic model was used to estimate DiNP daily intake from the MCiOP concentrations.

RESULTS

Creatinine-adjusted MCiOP urinary concentrations ranged from 0.42-80 μg/g in PVC film and from 1.11-13.4 μg/g in PVC compounding. PVC film participants who worked on a task using DiNP (n = 7) had the highest MCiOP geometric mean (GM) end-shift concentration (25.2 μg/g), followed by participants who worked on a shift where DiNP was used (n = 11) (17.7 μg/g) as compared to participants with no task (2.92 μg/g) or shift (2.08 μg/g) exposure to DiNP. The GM end-shift MCiOP concentration in PVC compounding participants (4.80 μg/g) was comparable to PVC film participants with no task or shift exposure to DiNP. Because no PVC compounding participants were assigned to tasks using DINP on the day sampled, DiNP exposure in this company may be underestimated. The highest DiNP intake estimate was 26 μg/kg/day.

CONCLUSION

Occupational exposure to DiNP associated with PVC film manufacturing tasks were substantially higher (sixfold to tenfold) than adult general population exposures; however, all daily intake estimates were less than 25% of current United States or European acceptable or tolerable daily intake estimates. Further characterization of DiNP occupational exposures in other industries is recommended.

Abstract LB-384: Elevated eIF4E phosphorylation is associated with advanced malignancy and decreased patient survival and can be therapeutically inhibited by a novel, orally bio-available Mnk inhibitor

Malignant progression & reduced patient survival have been linked to increased function of eukaryotic translation initiation factor 4E (eIF4E), which selectively enables translation of potent growth/survival factors & oncoproteins (e.g. c-myc, VEGF, cyclin D1, Mcl-1). Recent reports have shown that the oncogenic activity of eIF4E is critically dependent on the activity of MNK kinases (Map kinase interacting kinases 1 and 2). Furthermore, increased eIF4E phosphorylation, a consequence of Mnk activity, has been linked to advanced cancers, including head & neck & non-small cell lung cancers. Herein, by immunohistochemical analysis of 133 prostatic tissues from 76 men, we report that eIF4E phosphorylation is significantly elevated in human prostate cancers (CaP) in relation to disease progression. eIF4E phosphorylation is associated with advanced disease (trend analysis, p &lt; 0.0001) & is increased significantly in both low grade (Gleason score ≤ 6) & high grade (Gleason score ≥ 7) CaP vs. adjacent normal prostate tissue (BPH) (p &lt; 0.02 and p &lt; 0.0001, respectively). Elevated eIF4E phosphorylation in invasive prostate cancer CaP is related to significantly reduced patient survival (p = 0.0216) & increased risk of death from CaP (hazard ratio = 2.729). These data, along with data in experimental models implicating MNK activity in cellular transformation, indicate that therapeutic targeting of MNK activity may provide an attractive anti-cancer therapeutic strategy. Indeed, we now report the identification of a novel, small molecule Mnk inhibitor with IC50 values of 116 nm & 11nm against Mnk 1 & Mnk 2, respectively. This Mnk inhibitor suppresses eIF4E phosphorylation in a dose & time-dependent manner in a wide array of cancer cell lines, including melanomas, colorectal cancers, lymphomas, leukemias & prostate cancers. In HCT116 colon cancer, treatment with the Mnk inhibitor suppresses eIF4E phosphorylation and diminishes expression of the pro-survival factor Mcl-1. Mnk inhibitor treatment also suppresses cellular proliferation, induces apoptosis & dramatically diminishes soft agar colonization. Further, oral administration of this inhibitor suppresses eIF4E phosphorylation in normal mouse tissues and in xenografted human cancers within 30 minutes, lasting at least 4 hours in tumor tissue. Once daily (20mg/kg) or twice daily (10mg/kg) oral dosing significantly suppresses subcutaneous xenograft tumor growth. Moreover, oral dosing reduces dramatically the number and size of pulmonary metastases formed in mice injected intravenously with B16 melanoma cells & treated 12 consecutive days starting 1 day after cell injection. These data demonstrate the utility of this novel Mnk inhibitor in probing Mnk function in vitro & in vivo and highlight the potential anti-cancer therapeutic utility of suppressing Mnk function.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-384. doi:10.1158/1538-7445.AM2011-LB-384

Determinants of captan air and dermal exposures among orchard pesticide applicators in the Agricultural Health Study

OBJECTIVES

To identify and quantify determinants of captan exposure among 74 private orchard pesticide applicators in the Agricultural Health Study (AHS). To adjust an algorithm used for estimating pesticide exposure intensity in the AHS based on these determinants and to compare the correlation of the adjusted and unadjusted algorithms with urinary captan metabolite levels.

METHODS

External exposure metrics included personal air, hand rinse, and dermal patch samples collected from each applicator on 2 days in 2002-2003. A 24-h urine sample was also collected. Exposure determinants were identified for each external metric using multiple linear regression models via the NLMIXED procedure in SAS. The AHS algorithm was adjusted, consistent with the identified determinants. Mixed-effect models were used to evaluate the correlation between the adjusted and unadjusted algorithm and urinary captan metabolite levels.

RESULTS

Consistent determinants of captan exposure were a measure of application size (kilogram of captan sprayed or application method), wearing chemical-resistant (CR) gloves and/or a coverall/suit, repairing spray equipment, and product formulation. Application by airblast was associated with a 4- to 5-fold increase in exposure as compared to hand spray. Exposure reduction to the hands, right thigh, and left forearm from wearing CR gloves averaged ∼80%, to the right and left thighs and right forearm from wearing a coverall/suit by ∼70%. Applicators using wettable powder formulations had significantly higher air, thigh, and forearm exposures than those using liquid formulations. Application method weights in the AHS algorithm were adjusted to nine for airblast and two for hand spray; protective equipment reduction factors were adjusted to 0.2 (CR gloves), 0.3 (coverall/suit), and 0.1 (both).

CONCLUSIONS

Adjustment of application method, CR glove, and coverall weights in the AHS algorithm based on our exposure determinant findings substantially improved the correlation between the AHS algorithm and urinary metabolite levels.

Maternal exposure to polychlorinated biphenyls and the secondary sex ratio: an occupational cohort study

BACKGROUND

Though commercial production of polychlorinated biphenyls was banned in the United States in 1977, exposure continues due to their environmental persistence. Several studies have examined the association between environmental polychlorinated biphenyl exposure and modulations of the secondary sex ratio, with conflicting results.

OBJECTIVE

Our objective was to evaluate the association between maternal preconceptional occupational polychlorinated biphenyl exposure and the secondary sex ratio.

METHODS

We examined primipara singleton births of 2595 women, who worked in three capacitor plants at least one year during the period polychlorinated biphenyls were used. Cumulative estimated maternal occupational polychlorinated biphenyl exposure at the time of the infant's conception was calculated from plant-specific job-exposure matrices. A logistic regression analysis was used to evaluate the association between maternal polychlorinated biphenyl exposure and male sex at birth (yes/no).

RESULTS

Maternal body mass index at age 20, smoking status, and race did not vary between those occupationally exposed and those unexposed before the child's conception. Polychlorinated biphenyl-exposed mothers were, however, more likely to have used oral contraceptives and to have been older at the birth of their first child than non-occupationally exposed women. Among 1506 infants liveborn to polychlorinated biphenyl-exposed primiparous women, 49.8% were male; compared to 49.9% among those not exposed (n = 1089). Multivariate analyses controlling for mother's age and year of birth found no significant association between the odds of a male birth and mother's cumulative estimated polychlorinated biphenyl exposure to time of conception.

CONCLUSIONS

Based on these data, we find no evidence of altered sex ratio among children born to primiparous polychlorinated biphenyl-exposed female workers.

Estimated daily intake of phthalates in occupationally exposed groups

Improved analytical methods for measuring urinary phthalate metabolites have resulted in biomarker-based estimates of phthalate daily intake for the general population, but not for occupationally exposed groups. In 2003-2005, we recruited 156 workers from eight industries where materials containing diethyl phthalate (DEP), dibutyl phthalate (DBP), and/or di(2-ethylhexyl) phthalate (DEHP) were used as part of the worker's regular job duties. Phthalate metabolite concentrations measured in the workers' end-shift urine samples were used in a simple pharmacokinetic model to estimate phthalate daily intake. DEHP intake estimates based on three DEHP metabolites combined were 0.6-850 μg/kg/day, with the two highest geometric mean (GM) intakes in polyvinyl chloride (PVC) film manufacturing (17 μg/kg/day) and PVC compounding (12 μg/kg/day). All industries, except phthalate manufacturing, had some workers whose DEHP exposure exceeded the U.S. reference dose (RfD) of 20 μg/kg/day. A few workers also exceeded the DEHP European tolerable daily intake (TDI) of 50 μg/kg/day. DEP intake estimates were 0.5-170 μg/kg/day, with the highest GM in phthalate manufacturing (27 μg/kg/day). DBP intake estimates were 0.1-76 μg/kg/day, with the highest GMs in rubber gasket and in phthalate manufacturing (17 μg/kg/day, each). No DEP or DBP intake estimates exceeded their respective RfDs. The DBP TDI (10 μg/kg/day) was exceeded in three rubber industries and in phthalate manufacturing. These intake estimates are subject to several uncertainties; however, an occupational contribution to phthalate daily intake is clearly indicated in some industries.

Thyroxine and free thyroxine levels in workers occupationally exposed to inorganic lead

BACKGROUND

The effects of lead exposure on thyroid function are unclear.

METHODS

Serum thyroxine (T4) was evaluated among 137 lead-exposed workers and 83 non-exposed workers. Free thyroxine (FT4) was evaluated among a subset of these workers. Exposure metrics included blood lead level (BLL), which reflects recent exposure, zinc protoporphyrin (ZPP), a marker of intermediate-duration lead exposure, exposure duration, and estimated cumulative exposure. Multiple linear regression results were adjusted for age, race, and current smoking status.

RESULTS

Mean BLLs were 38.9 μg/dL in lead exposed workers and 2.1 μg/dL in non-exposed workers. The adjusted mean T4 and FT4 concentrations among exposed and non-exposed workers were similar. While T4 was not significantly related to any of the exposure metrics, FT4 was inversely related to the logged values of both exposure duration and cumulative exposure, but not to ZPP or BLL.

CONCLUSIONS

The findings suggest that FT4 levels may be related to long-term lead exposure.

Analysis of lognormally distributed exposure data with repeated measures and values below the limit of detection using SAS

Studies of determinants of occupational exposure frequently involve left-censored lognormally distributed data, often with repeated measures. Left censoring occurs when observations are below the analytical limit of detection (LOD); repeated measures data results from taking multiple measurements on the same worker. A common method of dealing with this type of data has been to substitute a value (such as LOD/2) for the censored data followed by statistical analysis using the 'usual' methods. Recently, maximum likelihood estimation (MLE) methods have been employed to reduce bias associated with the substitution method. We compared substitution and MLE methods using simulated lognormally distributed exposure data subjected to varying amounts of censoring using two procedures available in SAS: LIFEREG and NLMIXED. In these simulations, the MLE method resulted in less bias and performed well even for censoring up to 80%, whereas the substitution method resulted in considerable bias. We illustrate the NLMIXED procedure using a dataset of chlorpyrifos air measurements collected from termiticide applicators on consecutive days over a 5-day workweek. We provide sample SAS code for several situations including one and two groups, with and without repeated measures, random slopes, and nested random effects.

Risk of lung cancer associated with quantitative beryllium exposure metrics within an occupational cohort

OBJECTIVES

Beryllium has been identified as a human carcinogen on the basis of animal and epidemiological studies. The authors recently reported updated associations between lung cancer and beryllium exposure in a large, pooled occupational cohort. The authors conducted the present study to evaluate the shape of exposure-response associations between different exposure metrics and lung cancer in this cohort, considering potential confounders (race, plant, professional and short-term work status, and exposure to other lung carcinogens).

METHODS

The authors conducted Cox proportional hazards regression analyses of lung cancer risk with cumulative, mean and maximum 'daily weighted average' (DWA) exposure among 5436 workers, using age-based risk sets. Different exposure-response curves were fitted to the exposure metrics, including categorical, power, restricted cubic spline and piecewise log-linear fits.

RESULTS

The authors found significant positive associations between lung cancer and mean (p < 0.0001) and maximum (p < 0.0001) exposure, adjusting for age, birth cohort and plant, and for cumulative (p = 0.0017) beryllium exposure, adjusting for these factors plus short-term work status and exposure to asbestos. The best-fitting models were generally categorical or piecewise log-linear, with the steepest increase in lung cancer risk between 0 and 10 μg/m(3) for both mean and maximum DWA exposure and between 0 and 200 μg/m(3)-days for cumulative DWA exposure. The estimated mean DWA beryllium exposure associated with 10(-3) excess lifetime risk based on the piecewise log-linear model is 0.033 μg/m(3).

CONCLUSION

This study provides evidence that lung cancer risk is elevated at levels near the current US Occupational Safety and Health Administration beryllium exposure limit of 2.0 μg/m(3) DWA for workers.

Abstract 3451: Cell proliferation and apoptosis during chloroform-induced hepatocarcinogenesis in male F-344/N rats

The carcinogenic potential of chlorinated organics is of direct importance in human risk assessment. Most drinking water chlorinated organics are disinfection by products (DBPs) of water chlorination and many test positive in rodent bioassays. Trihalomethanes (THMs) are the most prevalent DBPs generated in chlorinated drinking water and chloroform (TCM) is the THM in highest concentration in finished drinking water. Human exposure to TCM occurs through ingestion of drinking water, inhalation and dermal exposure. TCM is carcinogenic to the liver and kidney of rodents including male and female B6C3F1 mice and male F-344/N and Osborne-Mendel rats. The carcinogenic mechanism of TCM in the rodent is not completely understood. Four mechanisms have been proposed: 1) mutagenicity; 2) reparative hyperplasia; 3) altered gene expression; and 4) secondary genotoxicity. Here, histopathology, immunohistochemistry, and quantitative image analysis were used to examine reparative cell proliferation and altered gene expression as potential mechanisms of TCM-induced hepatocellular carcinogenesis in male F-344/N rats. Animals were exposed to concentrations of 803 + 5 or 1592 + 21 mg/L in the drinking water for 78 or 100 weeks. Distilled water was the vehicle control. The high TCM dose increased the prevalence (% of animals with a lesion) of hepatocellular neoplasia (carcinoma and adenoma) 17.5% vs. 5.1% (p&lt;0.05) and marginally enhanced the prevalence of combined preneoplastic and neoplastic tumors (20.5% vs 7.7%; 0.05&lt;p&lt;0.1). Cell proliferation (proliferating cell nuclear antigen), apoptosis (terminal transferase assay) and expression of tumor associated markers, transforming growth factor alpha (TGF-α) and the p21 Ras oncogene were evaluated in normal liver, altered foci (AF), large foci of cellular alteration (LFCA) and adenomas (AD). PCNA, TGF-α, and p21 Ras increased significantly during TCM-induced neoplastic progression (p = 0.0021, 0.0105, and 0.0167, respectively). A significant change in apoptosis was not found during neoplastic progression, however, a progressive imbalance between cell proliferation and death occurred (p = 0.0022). The phenotype of hepatocellular lesions in rats receiving TCM in their drinking water differed from that of the “spontaneous” lesions arising in rats given distilled water, suggesting a different mechanistic origin. Taken together the data are consistent with a carcinogenic mechanism for TCM that includes adaptation to a hepatotoxic chemical and selection of resistant cells. (This abstract does not reflect the views of the EPA).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3451.

Abstract 1183: Association of germline variants of the TGFβR1 gene in colorectal cancer patients

Colorectal cancer is the second leading cause of cancer death in the United States and approximately 147,000 new cases of colorectal cancer (CRC) were expected in 2009. Most people with early colorectal cancer have no symptoms and symptoms usually only appear with more advanced disease. Therefore, susceptibility markers which could possibly identify patients at risk for colorectal cancer are important for earlier detection of the disease. Germline variations in the transforming growth factor beta (TGF-β) type I receptor (TGFβR1) have been found to be associated with several human cancers, in particular with advanced ovarian cancers, suggesting a role in advanced disease stage. We analyzed two genetic variants in the TGFβR1 gene for their association with colorectal cancer. One is an intronic variant, G→A polymorphism (Int7G24A), which is 24 base pairs downstream of the intron-exon 7 boundary. The other is a nine base pair deletion (TGFβR1*6A) in exon 1 of TGFβR1. Using capillary electrophoresis, we analyzed paraffin-embedded tissue specimens from 147 patients with CRC and 169 non-cancer controls. There was no difference between male and female non-cancer controls in the prevalence of either variant. When CRC cases were compared to non-cancer controls, it was found that the prevalence of TGFβR1*6A was not significantly increased (p = 0.11) but Int7G24A prevalence was significantly increased (p = 0.000039). For CRC cases and controls, the wild type genotype was compared to patients with either or both variants and a significant difference was found primarily due to the increased prevalence of Int7G24A in CRC patients (p = 0.000052). Int7G24A was more commonly found in invasive and metastatic CRC patients as compared to non-cancer controls (p = 0.00030). We conclude that Int7G24A is a potential susceptibility marker for CRC and is associated with advanced disease stage.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1183.

eIF4E activation is commonly elevated in advanced human prostate cancers and significantly related to reduced patient survival

Elevated eukaryotic translation initiation factor 4E (eIF4E) function induces malignancy in experimental models by selectively enhancing translation of key malignancy-related mRNAs (c-myc and BCL-2). eIF4E activation may reflect increased eIF4E expression or phosphorylation of its inhibitory binding proteins (4E-BP). By immunohistochemical analyses of 148 tissues from 89 prostate cancer patients, we now show that both eIF4E expression and 4E-BP1 phosphorylation (p4E-BP1) are increased significantly, particularly in advanced prostate cancer versus benign prostatic hyperplasia tissues. Further, increased eIF4E and p4E-BP1 levels are significantly related to reduced patient survival, whereas uniform 4E-BP1 expression is significantly related to better patient survival. Both immunohistochemistry and Western blotting reveal that elevated eIF4E and p4E-BP1 are evident in the same prostate cancer tissues. In two distinct prostate cancer cell models, the progression to androgen independence also involves increased eIF4E activation. In these prostate cancer cells, reducing eIF4E expression with an eIF4E-specific antisense oligonucleotide currently in phase I clinical trials robustly induces apoptosis, regardless of cell cycle phase, and reduces expression of the eIF4E-regulated proteins BCL-2 and c-myc. Collectively, these data implicate eIF4E activation in prostate cancer and suggest that targeting eIF4E may be attractive for prostate cancer therapy.

Occupational exposure to polychlorinated biphenyls and risk of breast cancer

BACKGROUND

Despite the endocrine system activity exhibited by polychlorinated biphenyls (PCBs), recent studies have shown little association between PCB exposure and breast cancer mortality.

OBJECTIVES

To further evaluate the relation between PCB exposure and breast cancer risk, we studied incidence, a more sensitive end point than mortality, in an occupational cohort.

METHODS

We followed 5,752 women employed for at least 1 year in one of three capacitor manufacturing facilities, identifying cases from questionnaires, cancer registries, and death certificates through 1998. We collected lifestyle and reproductive information via questionnaire from participants or next of kin and used semiquantitative job-exposure matrices for inhalation and dermal exposures combined. We generated standardized incidence ratios (SIRs) and standardized rate ratios and used Cox proportional hazards regression models to evaluate potential confounders and effect modifiers.

RESULTS

Overall, the breast cancer SIR was 0.81 (95% confidence interval, 0.72-0.92; n = 257), and regression modeling showed little effect of employment duration or cumulative exposure. However, for the 362 women of questionnaire-identified races other than white, we observed positive, statistically significant associations with employment duration and cumulative exposure; only smoking, birth cohort, and self- or proxy questionnaire completion had statistically significant explanatory power when added to models with exposure metrics.

CONCLUSIONS

We found no overall elevation in breast cancer risk after occupational exposure to PCBs. However, the exposure-related risk elevations seen among nonwhite workers, although of limited interpretability given the small number of cases, warrant further investigation, because the usual reproductive risk factors accounted for little of the increased risk.

Urinary phthalate metabolite concentrations among workers in selected industries: a pilot biomonitoring study

Phthalates are used as plasticizers and solvents in industrial, medical and consumer products; however, occupational exposure information is limited. We sought to obtain preliminary information on occupational exposures to diethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) by analyzing for their metabolites in urine samples collected from workers in a cross-section of industries. We also obtained data on metabolites of dimethyl phthalate (DMP), benzylbutyl phthalate (BzBP), di-isobutyl phthalate and di-isononyl phthalate. We recruited 156 workers in 2003-2005 from eight industry sectors. We assessed occupational contribution by comparing end-shift metabolite concentrations to the US general population. Evidence of occupational exposure to DEHP was strongest in polyvinyl chloride (PVC) film manufacturing, PVC compounding and rubber boot manufacturing where geometric mean (GM) end-shift concentrations of DEHP metabolites exceeded general population levels by 8-, 6- and 3-fold, respectively. Occupational exposure to DBP was most evident in rubber gasket, phthalate (raw material) and rubber hose manufacturing, with DBP metabolite concentrations exceeding general population levels by 26-, 25- and 10-fold, respectively, whereas DBP exposure in nail-only salons (manicurists) was only 2-fold higher than in the general population. Concentrations of DEP and DMP metabolites in phthalate manufacturing exceeded general population levels by 4- and >1000-fold, respectively. We also found instances where GM end-shift concentrations of some metabolites exceeded general population concentrations even when no workplace use was reported, e.g. BzBP in rubber hose and rubber boot manufacturing. In summary, using urinary metabolites, we successfully identified workplaces with likely occupational phthalate exposure. Additional work is needed to distinguish occupational from non-occupational sources in low-exposure workplaces.

Adjustment for temporal confounders in a reanalysis of a case-control study of beryllium and lung cancer

OBJECTIVES

To evaluate potential confounding of the association between beryllium and lung cancer in a reanalysis of data from a published case-control study of workers at a beryllium processing facility.

METHODS

The association of cumulative and average beryllium exposure with lung cancer among 142 cases and five age-match controls per case was reanalysed using conditional logistic regression. Adjustment was made independently for potential confounders of hire age and birth year. Alternative adjustments to avoid taking the logarithm of zero were explored.

RESULTS

Adjustment for either birth cohort or hire age (two highly correlated factors) attenuated lung cancer risk associated with cumulative exposure; however, lung cancer risk was significantly associated with average exposure using a 10-year lag following adjustment. Stratification of analyses by birth cohort found greater lung cancer risk from cumulative and average exposure for workers born before 1900 than for workers born later. The magnitude of the association between lung cancer and average exposure was not reduced by modifying the method used to take the log of exposure.

CONCLUSION

In this reanalysis, average, but not cumulative, beryllium exposure was related to lung cancer risk after adjustment for birth cohort. Confounding by birth cohort is likely related to differences in smoking patterns for workers born before 1900 and the tendency for workers hired during the World War II era to have been older at hire.

Captan exposure and evaluation of a pesticide exposure algorithm among orchard pesticide applicators in the Agricultural Health Study

Pesticide exposure assessment in the Agricultural Health Study (AHS) has relied upon two exposure metrics: lifetime exposure days and intensity-weighted lifetime exposure days, the latter incorporating an intensity score computed from a questionnaire-based algorithm. We evaluated this algorithm using actual fungicide exposure measurements from AHS private orchard applicators. Captan was selected as a marker of fungicide exposure. Seventy-four applicators from North Carolina and Iowa growing apples and/or peaches were sampled on 2 days they applied captan in 2002 and 2003. Personal air, hand rinse, 10 dermal patches, a pre-application first-morning urine and a subsequent 24-h urine sample were collected from each applicator per day. Environmental samples were analyzed for captan, and urine samples were analyzed for cis-1,2,3,6-tetrahydrophthalimide (THPI). Task and personal protective equipment information needed to compute an individual's algorithm score was also collected. Differences in analyte detection frequency were tested in a repeated logistic regression model. Mixed-effects models using maximum-likelihood estimation were employed to estimate geometric mean exposures and to evaluate the measured exposure data against the algorithm. In general, captan and THPI were detected significantly more frequently in environmental and urine samples collected from applicators who used air blast sprayers as compared to those who hand sprayed. The AHS pesticide exposure intensity algorithm, while significantly or marginally predictive of thigh and forearm captan exposure, respectively, did not predict air, hand rinse or urinary THPI exposures. The algorithm's lack of fit with some exposure measures among orchard fungicide applicators may be due in part to the assignment of equal exposure weights to air blast and hand spray application methods in the current algorithm. Some modification of the algorithm is suggested by these results.

Resident cleanup activities, characteristics of flood-damaged homes and airborne microbial concentrations in New Orleans, Louisiana, October 2005

BACKGROUND

Flooding in the greater New Orleans (GNO) area after the hurricanes caused extensive mold growth in homes resulting in public health concerns.

OBJECTIVES

We conducted an environmental assessment of homes to determine the extent and type of microbial growth.

METHODS

We randomly selected 112 homes, stratified by water damage, and then visually assessed mold growth. Air samples from a subset of 20 homes were analyzed for culturable fungi, fungal spores, and markers of mold ((1-->3, 1-->6)-beta-D-glucans) and bacteria (endotoxin).

RESULTS

Visible mold growth occurred in 49 (44%) homes; 18 (16%) homes had >50% mold coverage. Flood levels were >6 ft at 20 (19%), 3-6 ft at 20 (19%), and <3 ft at 28 (26%) homes out of 107; no flooding at 39 (36%) homes. The residents spent an average of 18 h (range: 1-84) doing heavy cleaning and of those, 22 (38%) reported using an N-95 or other respirator. Visible mold growth was significantly associated with flood height 3 ft and the predominant fungi indoors were Aspergillus and Penicillium species, which were in higher concentrations in homes with a flood level 3 ft. Geometric mean (GM) levels of endotoxin were as high as 40.2 EU/m(3), while GM glucan levels were as high as 3.5 microg/m(3) even when flooding was 3 ft.

CONCLUSIONS

Based on our observations of visible mold, we estimated that elevated mold growth was present in 194,000 (44%) homes in the GNO area and 70,000 (16%) homes had heavy mold growth. Concentrations of endotoxin and glucans exceeded those previously associated with health effects. With such high levels of microbial growth following flooding, potentially harmful inhalation exposures can be present for persons entering or cleaning affected homes. Persons exposed to water-damaged homes should follow the CDC recommendations developed following the 2005 hurricanes for appropriate respiratory precautions.

A comparison of two methods for estimating prevalence ratios

BACKGROUND

It is usually preferable to model and estimate prevalence ratios instead of odds ratios in cross-sectional studies when diseases or injuries are not rare. Problems with existing methods of modeling prevalence ratios include lack of convergence, overestimated standard errors, and extrapolation of simple univariate formulas to multivariable models. We compare two of the newer methods using simulated data and real data from SAS online examples.

METHODS

The Robust Poisson method, which uses the Poisson distribution and a sandwich variance estimator, is compared to the log-binomial method, which uses the binomial distribution to obtain maximum likelihood estimates, using computer simulations and real data.

RESULTS

For very high prevalences and moderate sample size, the Robust Poisson method yields less biased estimates of the prevalence ratios than the log-binomial method. However, for moderate prevalences and moderate sample size, the log-binomial method yields slightly less biased estimates than the Robust Poisson method. In nearly all cases, the log-binomial method yielded slightly higher power and smaller standard errors than the Robust Poisson method.

CONCLUSION

Although the Robust Poisson often gives reasonable estimates of the prevalence ratio and is very easy to use, the log-binomial method results in less bias in most common situations, and because it fits the correct model and obtains maximum likelihood estimates, it generally results in slightly higher power, smaller standard errors, and, unlike the Robust Poisson, it always yields estimated prevalences between zero and one.

A comparison of two methods for estimating prevalence ratios

Background

It is usually preferable to model and estimate prevalence ratios instead of odds ratios in cross-sectional studies when diseases or injuries are not rare. Problems with existing methods of modeling prevalence ratios include lack of convergence, overestimated standard errors, and extrapolation of simple univariate formulas to multivariable models. We compare two of the newer methods using simulated data and real data from SAS online examples.

Methods

The Robust Poisson method, which uses the Poisson distribution and a sandwich variance estimator, is compared to the log-binomial method, which uses the binomial distribution to obtain maximum likelihood estimates, using computer simulations and real data.

Results

For very high prevalences and moderate sample size, the Robust Poisson method yields less biased estimates of the prevalence ratios than the log-binomial method. However, for moderate prevalences and moderate sample size, the log-binomial method yields slightly less biased estimates than the Robust Poisson method. In nearly all cases, the log-binomial method yielded slightly higher power and smaller standard errors than the Robust Poisson method.

Conclusion

Although the Robust Poisson often gives reasonable estimates of the prevalence ratio and is very easy to use, the log-binomial method results in less bias in most common situations, and because it fits the correct model and obtains maximum likelihood estimates, it generally results in slightly higher power, smaller standard errors, and, unlike the Robust Poisson, it always yields estimated prevalences between zero and one.

Issues when modeling benzene, toluene, and xylene exposures using a literature database

A database of benzene, toluene, and xylene measurements was compiled from an extensive literature review that contained information on several exposure determinants, including job type, operation, mechanism of release, process type, ventilation, temperature, distance from the source, quantity, and location. The database was used to develop statistical models for benzene, toluene, and xylene exposure as a function of operation and other workplace determinants. These models can be used to predict exposure levels for subjects enrolled in community-based case-control studies. This article presents the derived parameter estimates for specific operations and additional workplace exposure determinants and describes a number of statistical and data limitation issues that are inherent in determinants modeling of historical published data. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource(s): a PDF file of QQ plots and a Word file with references used in the benzene/toluene/xylene exposure database].