A Unifying Framework for Understanding Biological Structures and Functions Across Levels of Biological Organization

The relationship between structure and function is a major constituent of the rules of life. Structures and functions occur across all levels of biological organization. Current efforts to integrate conceptual frameworks and approaches to address new and old questions promise to allow a more holistic and robust understanding of how different biological functions are achieved across levels of biological organization. Here, we provide unifying and generalizable definitions of both structure and function that can be applied across all levels of biological organization. However, we find differences in the nature of structures at the organismal level and below as compared to above the level of the organism. We term these intrinsic and emergent structures, respectively. Intrinsic structures are directly under selection, contributing to the overall performance (fitness) of the individual organism. Emergent structures involve interactions among aggregations of organisms and are not directly under selection. Given this distinction, we argue that while the functions of many intrinsic structures remain unknown, functions of emergent structures are the result of the aggregate of processes of individual organisms. We then provide a detailed and unified framework of the structure-function relationship for intrinsic structures to explore how their unknown functions can be defined. We provide examples of how these scalable definitions applied to intrinsic structures provide a framework to address questions on structure-function relationships that can be approached simultaneously from all subdisciplines of biology. We propose that this will produce a more holistic and robust understanding of how different biological functions are achieved across levels of biological organization.

Psychosocial adjustment mediates impacts of playmate positive support on body mass index and overweight risk in adolescents

OBJECTIVES

We examined the mediation effects of psychosocial adjustment on the impact of playmate positive support throughout childhood and early adolescence (from age 54 months to 11 years) on later body mass index (BMI) and overweight risk in middle adolescence (age 15 years).

STUDY DESIGN

This was a prospective cohort study.

METHODS

Among 844 children and their families, positive support between child-playmate dyads was repeatedly assessed from child's age 54 months to Grade 5. Long-term positive support between child-playmate dyads throughout childhood and early adolescence was prospectively linked to child's BMI and overweight/obesity status at age 15 years. The average scores of repeated assessments of internalizing and externalizing behavior problems from Grades 3 to 6 were used as mediators.

RESULTS

Significant mediations of internalizing and externalizing behavior problems were observed on pathways from positive support between child-playmate dyads to later BMI and overweight/obesity status at age 15 years. The observed mediations were mainly sustained with pronounced magnitudes in girls, but not in boys.

CONCLUSIONS

Our findings demonstrated a significant mediating role of psychosocial adjustment. Future research efforts are highly encouraged to replicate our findings and further explore this underlying mediation mechanism.

POS0417 EXOGENOUS CXCL5 RESTORES ENDOGENOUS BLOOD-TISSUE CHEMOKINE GRADIENT TO IMPROVE SURVIVAL IN MURINE LUPUS

Background:

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease that is potentially fatal. There is an unmet need to improve current therapies. In patients with SLE, we observed that serum CXCL5 levels were significantly lower than healthy control subjects and negatively correlated with disease activity(1-9).

Objectives:

The aim of this study is to elucidate the effect of supplemental serum CXCL5 in abrogating the pathological processes of SLE.

Methods:

Ten doses of exogenous CXCL5 (3µg/kg) was administered to 16-week-old Faslpr mice weekly by intravenous injection. Mice were monitored for 10 weeks. Splenic immune profile was measured by flow cytometry. Circulating cytokine and immunoglobulin profile were detected by Luminex technology. Renal function was evaluated by urinary spot albumin creatinine ratio. In situ renal immune cell infiltration and complement 3 deposition were detected by Haematoxylin and Eosin (H&E) and immunohistochemistry staining. The molecular pathways involved were examined by RNA sequencing.

Results:

In Faslpr mice, intravenous administration of exogenous CXCL5 significantly improved mouse survival with concomitant reduction of autoantibody secretion, proteinuria, complement 3 deposition, neutrophil infiltration and lupus nephritis classes. Through evaluating the changes of immune profile, cytokine profile and molecular pathways, we found that intravenous CXCL5 reduced inflammation via an orchestral effect of regulating neutrophil trafficking and modulating helper T cell-mediated immune response. Pharmacokinetic and real-time Polymerase Chain Reaction studies further demonstrated that this orchestration was triggered by a cascade reaction - restoring vascular under-expressed CXCL5 by an exogenous stimulation, re-establishing the normal serum levels of endogenous CXCL5 and reverting the CXCL5 chemokine gradient between inflamed tissues and blood circulation.

Conclusion:

Managing the dysregulation of CXCL5 by exogenous supplement may provide a new option for SLE therapy.

References:

[1]Dufies M, Grytsai O, Ronco C, et al. New CXCR1/CXCR2 inhibitors represent an effective treatment for kidney or head and neck cancers sensitive or refractory to reference treatments. Theranostics. 2019;9(18):5332-5346. doi:10.7150/thno.34681

[2]Yildirim K, Colak E, Aktimur R, et al. Clinical Value of CXCL5 for Determining of Colorectal Cancer. Asian Pac J Cancer Prev. Sep 26 2018;19(9):2481-2484. doi:10.22034/apjcp.2018.19.9.2481

[3]Wu K, Yu S, Liu Q, Bai X, Zheng X. The clinical significance of CXCL5 in non-small cell lung cancer. Onco Targets Ther. 2017;10:5561-5573. doi:10.2147/ott.s148772

[4]Zhao J, Ou B, Han D, et al. Tumor-derived CXCL5 promotes human colorectal cancer metastasis through activation of the ERK/Elk-1/Snail and AKT/GSK3beta/beta-catenin pathways. Mol Cancer. Mar 29 2017;16(1):70. doi:10.1186/s12943-017-0629-4

[5]Han KQ, Han H, He XQ, et al. Chemokine CXCL1 may serve as a potential molecular target for hepatocellular carcinoma. Cancer Med. Oct 2016;5(10):2861-2871. doi:10.1002/cam4.843

[6]Pappa CA, Tsirakis G, Kanellou P, et al. Monitoring serum levels ELR+ CXC chemokines and the relationship between microvessel density and angiogenic growth factors in multiple myeloma. Cytokine. Dec 2011;56(3):616-20. doi:10.1016/j.cyto.2011.08.034

[7]Zhang L, Li H, Ge C, et al. CXCL3 contributes to CD133(+) CSCs maintenance and forms a positive feedback regulation loop with CD133 in HCC via Erk1/2 phosphorylation. Sci Rep. Jun 3 2016;6:27426. doi:10.1038/srep27426

[8]Matsubara J, Honda K, Ono M, et al. Reduced plasma level of CXC chemokine ligand 7 in patients with pancreatic cancer. Cancer Epidemiol Biomarkers Prev. Jan 2011;20(1):160-71. doi:10.1158/1055- 9965.epi-10-0397

[9]Ma Y, Ren Y, Dai ZJ, Wu CJ, Ji YH, Xu J. IL-6, IL-8 and TNF-alpha levels correlate with disease stage in breast cancer patients. Adv Clin Exp Med. May-Jun 2017;26(3):421-426. doi:10.17219/acem/62120

Disclosure of Interests:

None declared

AB0128 CXCL5 DAMPENS INFLAMMATION IN THE PRE-CLINICAL MODEL OF SYSTEMIC LUPUS ERYTHEMATOSUS VIA THE ORCHESTRAL EFFECT OF REGULATING NEUTROPHIL TRAFFICKING AND SUPPRESSING HELPER T CELL-MEDIATED IMMUNE RESPONSE

Background:

Patients with systemic lupus erythematosus (SLE) suffer from severe morbidity and mortality1-4, either from the disease itself or from side effects of immunosuppression5. Discovery of novel effective therapies with less toxicity is an urgent need.

Objectives:

The aim of this study is to elucidate the therapeutic potential and working mechanism of cytokine CXCL5 in lupus mice.

Methods:

Treatment with CXCL5, bone marrow (BM)-MSCs, standard of care (SOC) with combination of methylprednisolone and cyclophosphamide was given to 16-week-old Faslprmice. Mice were monitored for 10 weeks. Splenic immune cell subsets were measured by flow cytometry. Circulating cytokine and immunoglobulin were detected by Luminex technology. Renal function was evaluated by urinary spot albumin creatinine ratio. In situ renal immune cell infiltration and complement 3 deposition were detected by Haematoxylin and Eosin (H&E) staining and immunohistochemistry.

Results:

CXCL5 demonstrated consistent and potent immunosuppressive capacity in suppressing SLE with reduced autoantibody secretion, lymphoproliferation and preserved kidney function. With further exploration, we proved that CXCL5 reduced the proliferation of helper T cells (TH1 and TH2) in thein vitrofunctional assay. When we administrated CXCL5 to lupus mice, it promoted the proliferation of regulatory T cells and reduced the proliferation of TH17 cells, macrophages and neutrophils. Multiple proinflammatory cytokines including IL-2, IL-6, IL-12, IL-17A, KC/CXCL1, MIP-1β/CCL4 and TNF-α were also reduced. When combined with SOC, CXCL5 boosted its therapeutic effect and reduced the relevant indices of disease activity. When we correlated the effect of four different treatment groups (CXCL5, BM-MSCs, SOC, and CXCL5 plus SOC) on mice survival and target cell changes, we found that TH17 cells were the key effector cells involved in the pathogenesis of SLE.

Conclusion:

These findings demonstrated that CXCL5 dampens inflammation in the pre-clinical model of systemic lupus erythematosus via the orchestral effect of regulating neutrophil trafficking and suppressing helper T cell-mediated immune response. Administrating exogenous CXCL5 might be an attractive option to treat patients with lupus.

References:

[1]Ji S, Guo Q, Han Y, Tan G, Luo Y, Zeng F. Mesenchymal stem cell transplantation inhibits abnormal activation of Akt/GSK3beta signaling pathway in T cells from systemic lupus erythematosus mice.Cell Physiol Biochem.2012;29(5-6):705-712.

[2]Peng SL. Altered T and B lymphocyte signaling pathways in lupus.Autoimmun Rev.2009;8(3):179-183.

[3]Ferucci ED, Johnston JM, Gaddy JR, et al. Prevalence and incidence of systemic lupus erythematosus in a population-based registry of American Indian and Alaska Native people, 2007-2009.Arthritis Rheumatol.2014;66(9):2494-2502.

[4]Jakes RW, Bae SC, Louthrenoo W, Mok CC, Navarra SV, Kwon N. Systematic review of the epidemiology of systemic lupus erythematosus in the Asia-Pacific region: prevalence, incidence, clinical features, and mortality.Arthritis Care Res (Hoboken).2012;64(2):159-168.

[5]Sattwika PD, Mustafa R, Paramaiswari A, Herningtyas EH. Stem cells for lupus nephritis: a concise review of current knowledge.Lupus.2018;27(12):1881-1897.

Acknowledgments:

The work was supported by SMART II Centre Grant (NMRC/CG/M011/2017_SGH) and SingHealth Foundation (SHF/FG638P/2016).

Disclosure of Interests:

None declared

Impact of Balloon-Guiding Catheter Location on Recanalization in Patients with Acute Stroke Treated by Mechanical Thrombectomy

BACKGROUND AND PURPOSE

Mechanical thrombectomy with proximal flow control and forced aspiration may improve the outcome of endovascular revascularization therapy for patients with acute stroke. The purpose of this study was to compare the impact of balloon-guiding catheter locations in patients treated for anterior circulation acute ischemic stroke using mechanical thrombectomy.

MATERIALS AND METHODS

The influence of the balloon-guiding catheter location (proximal, balloon-guiding catheter tip proximal to C1 vertebral body; distal, between the skull base and the C1 vertebral body) was analyzed in patients with acute anterior circulation stroke treated with stent-retriever thrombectomy. The baseline angiographic/clinical characteristics, time intervals, recanalization rates, and clinical outcomes were compared.

RESULTS

The clinical analysis included 102 patients (mean age, 69.5 ± 12.8 years; male/female ratio = 52:50). The balloon-guiding catheter was located distally in 49 patients and proximally in 53 patients for flow control and forced aspiration during stent retrieval. The puncture-to-recanalization time was shorter in the distal group than in the proximal group (40 versus 56 minutes, P = .02). Successful and complete recanalizations were more frequently achieved in the distal group compared with the proximal group (98.0% versus 75.5%. P = .003; 67.3% versus 45.3%, P = .04, respectively). Multivariate analysis showed that the distal catheterization location was independently associated with successful recanalization (adjusted OR, 13.4; 95% CI, 2.4-254.8; P = .02).

CONCLUSIONS

Location of the balloon-guiding catheter has a significant impact on recanalization in patients with acute stroke. The balloon-guiding catheter should be positioned as distally as safely possible in the cervical ICA for maximally effective thrombectomy.

Isomorphic coalescence of aster cores formed in vitro from microtubules and kinesin motors

We report fluorescence microscopy studies of the formation of aster-like structures emerging from a cellular element-based active system and a novel analysis of the aster condensation. The system consists of rhodamine labeled microtubules which are dynamically coupled by functionalized kinesin motor proteins cross-linked via streptavidin-coated quantum dots (QDs). The aster-shaped objects contain core structures. The cores are aggregates of the QD-motor protein complexes, and result from the dynamic condensation of sub-clusters that are connected to each other randomly. The structural specificity of the aster core reflects a configuration of the initial connectivity between sub-clusters. Detailed image analysis allows us to extract a novel correlation between the condensation speed and the sub-cluster separation. The size of the core is scaled down during the condensation process, following a power law dependence on the distance between sub-clusters. The exponent of the power law is close to two, as expected from a geometric model. This single exponent common to all the contractile lines implies that there exists a time regime during which an isomorphic contraction of the aster core continues during the condensation process. We analyze the observed contraction by using a model system with potential applicability in a wide range of emergent phenomena in randomly coupled active networks, which are prevalent in the cellular environment.

Towards a global system of vigilance and surveillance in unrelated donors of haematopoietic progenitor cells for transplantation

Safety of living donors is critical to the success of blood, tissue and organ transplantation. Structured and robust vigilance and surveillance systems exist as part of some national entities, but historically no global systems are in place to ensure conformity, harmonisation and the recognition of rare adverse events (AEs). The World Health Assembly has recently resolved to require AE/reaction (AE/R) reporting both nationally and globally. The World Marrow Donor Association (WMDA) is an international organisation promoting the safety of unrelated donors and progenitor cell products for use in haematopoietic progenitor cell (HPC) transplantation. To address this issue, we established a system for collecting, collating, analysing, distributing and reacting to serious adverse events and reactions (SAE/R) in unrelated HPC donors. The WMDA successfully instituted this reporting system with 203 SAE/R reported in 2011. The committee generated two rapid reports, reacting to specific SAE/R, resulting in practice changing policies. The system has a robust governance structure, formal feedback to the WMDA membership and transparent information flows to other agencies, specialist physicians and transplant programs and the general public.

Insight into the sharing of medical images: physician, other health care providers, and staff experience in a variety of medical settings

BACKGROUND

Scant knowledge exists describing health care providers' and staffs' experiences sharing imaging studies. Additional research is needed to determine the extent to which imaging studies are shared in diverse health care settings, and the extent to which provider or practice characteristics are associated with barriers to viewing external imaging studies on portable media.

OBJECTIVE

This analysis uses qualitative data to 1) examine how providers and their staff accessed outside medical imaging studies, 2) examine whether use or the desire to use imaging studies conducted at outside facilities varied by provider specialty or location (urban, suburban, and small town) and 3) delineate difficulties experienced by providers or staff as they attempted to view and use imaging studies available on portable media.

METHODS

Semi-structured interviews were conducted with 85 health care providers and medical facility staff from urban, suburban, and small town medical practices in North Carolina and Virginia. The interviews were audio recorded, transcribed, then systematically analyzed using ATLAS.ti.

RESULTS

Physicians at family and pediatric medicine practices rely primarily on written reports for medical studies other than X-rays; and thus do not report difficulties accessing outside imaging studies. Subspecialists in urban, suburban, and small towns view imaging studies through internal communication systems, internet portals, or portable media. Many subspecialists and their staff report experiencing difficulty and time delays in accessing and using imaging studies on portable media.

CONCLUSION

Subspecialists have distinct needs for viewing imaging studies that are not shared by typical primary care providers. As development and implementation of technical strategies to share medical records continue, this variation in need and use should be noted. The sharing and viewing of medical imaging studies on portable media is often inefficient and fails to meet the needs of many subspeciality physicians, and can lead to repeated imaging studies.

The anti-tumour activity of allogeneic cytokine-induced killer cells in patients who relapse after allogeneic transplant for haematological malignancies

We performed a Phase I/II clinical trial to study the feasibility, toxicity and efficacy of allogeneic cytokine-induced killer (CIK) cell expansion, and treatment for patients with haematological malignancies who relapsed after allogeneic haemopoietic SCT (allo-HSCT). Allogeneic CIK cells were successfully generated for a total of 24 patients, including those from patients' own leukapheresis products in 5 patients who had no access to further donor cells. The median CD3(+) T-cell expansion was 9.33 (1.3-38.97) fold, and CD3(+)CD56(+) natural killer (NK)-like T-cell expansion was 27.77 (2.59-438.93) fold. A total of 55 infusions were done for 16 patients who had either failed or progressed after initial response to various individualized chemotherapy regimens and donor lymphocyte infusion (DLI), at doses ranging from 10 to 200 million CD3(+) cells/kg. Response attributable to CIK cell infusion was observed in five patients. These included two with ALL, two with Hodgkin's disease (HD) and one with AML, and two of whom had a response sustained for more than 2 years. Acute GVHD occurred in three and was easily treatable. This study provides some evidence suggestive of the efficacy of allogeneic CIK cells even after failure of DLI in some cases.

The biology and prognostic value of lymphatic vessel density (LD) and lymphatic invasion (LI) in regression in melanoma

9017

Background: Regression in melanoma is characterized by increased vascularity, lymphocytic infiltrate and fibroplasia in the papillary dermis, accompanied by the absence (complete regression, CoR) or presence (partial regression, PaR) of melanoma cells in the epidermis. The prognostic value of regression is controversial. We noticed that LD and LI were increased in the areas of regression (AR) or areas with brisk lymphocytic infiltration (AB). Our goal was to clarify the prognostic value of regression in melanoma. Methods: Dual immunohistochemical staining was done using antibodies to podoplanin (lymphatic vessels) and S100 (melanoma cells) on paraffin tissues from 321 patients with vertical growth phase (VGP) primary melanomas who had 10 years or more of follow-up. LD in AR (both CoR and PaR) was compared with that of normal dermis adjacent and distant, as well as LD in the AB. LI in these areas was also scored. Unadjusted and adjusted hazard rates were obtained from univariate and multivariate Cox models for time to melanoma-specific death using established melanoma prognostic factors. Results: 116 patients (36%) had regression: 75 CoR (23%) and 41 PaR (13%). LD significantly decreased stepwise from CoR (mean ± se, 23.7 ± 2.7) to PaR (15.5 ± 1.1), adjacent normal dermis (7.3 ± 0.28) and distant normal dermis (5.4±0.31) and it was significantly elevated in the AB (18.5±0.78). Melanomas with CoR had the highest percentage of LI in both AR and AB. In addition, the percentage of LI in AB was highest for men and for those with VGP tumor infiltrating lymphocytes (TILs). Both high LD in AR and more LI in AB were associated with poor prognosis (p=0.004 and p=0.002, respectively). Six factors were significant in the final multivariate model: LI in AB (HR=2.3), LD in AR (HR=1.04), thickness (HR=1.44), axial (HR=7.7), ulceration (HR=2.5) and no VGP TILs (HR=2.8). Conclusions: AR and AB were associated with increased LD and higher incidence of LI in primary melanomas. LD and LI in AR or AB are independent prognostic factors. Our data suggest that the effects of regression on prognosis are mediated at least in part through lymphangiogenesis and LI.

No significant financial relationships to disclose.

The relationship between adherence to adjuvant hormonal therapy and survival among low-income, insured women with primary breast cancer

e11522

Background: Clinical trials and meta-analyses show that adjuvant hormonal therapy for hormone receptor positive breast cancer significantly decreases risk of death. We explored the relationship between adherence to adjuvant hormonal therapy and death in a low-income, Medicaid-insured population. Methods: Using a Medicaid claims-tumor registry linked database and National Death Index data (NDI), we evaluated adherence to adjuvant hormonal therapy [defined as >80% Medication Possession Ratio (MPR)] and mean six-year overall and cancer-specific survival by local versus regional stage for all female breast cancer diagnosed in years 2000–2002, in North Carolina. The Kaplan-Meier and Cox Proportional Hazards models were used to determine the role of adherence on cancer-specific survival. Models were adjusted for age, race, Charlson comorbidity score, number of prescription medications, type of surgery, use of radiation therapy, prior chemotherapy, hormone receptor status (positive or unknown). Results: The final sample consisted of 1,042 cases [ages range 29–97 years (mean 65.9 years; 56% Caucasian; mean Charlson comorbidity score 4.1 (SD 2.9); 680 local and 362 regional stage], of which 732 filled a prescription for adjuvant hormonal therapy within the year after breast cancer diagnosis. Filling a prescription for adjuvant hormonal therapy, versus not, was not significantly associated with cancer-related death: HR 1.04 (95% CI 0.66 - 1.64) overall; HR 0.75 (95% CI 0.39 - 1.43) for local stage and HR 1.01 (95% CI 0.51 - 2.00) for regional stage. However, adherence in the highest quartile (MPR>95) is associated with an increase in mortality risk. Conclusions: In this low income insured group of breast cancer patients, no statistically significant association was found between death rates and use of adjuvant hormonal therapy. However, an unexpected association between very high adherence and increase in mortality was found. This may reflect methodological limitations of claims data involving bias and unidentified patient risk. More research is needed to explore reasons for higher mortality among low-income women with high medication adherence.

[Table: see text]

Prognostic risk group classification for patients (pts.) with platinum-refractory metastatic urothelial cancer (UC) treated with second-line chemotherapy

5078

Background: Second-line chemotherapy in pts. with platinum-refractory metastatic UC is associated with low objective response rates and short progression-free and overall survival. Prognostic risk groups in this setting have not been reported. Methods: We studied 151 pts. with platinum-refractory metastatic UC treated with second-line vinflunine (VFL) (Vaughn, GU Cancer Symposium. 2008). Using progression at 6 months as the primary endpoint, baseline patient characteristics were examined in univariate and multivariate analyses. Multivariate logistic regression was used to identify independent predictors of progression at 6 months, and the variable selection result was validated by nonparametric bootstrap. Risk scores were generated from summing the relative importance of the factors identified on multivariate analysis. Patients were classified into risk groups and compared. Results: Of the 151 pts., 80% were male, 54% were aged > 65 years, and 68% had Karnofsky performance status (KPS) > 90%. 115 pts. (76%) progressed or died by 6 months after initiating VFL. The factors associated with an increased odds ratio (OR) for disease progression at 6 months were presence of visceral metastases (OR 8.08; p < 0.001; 2 points), KPS < 90% (OR 6.63; p = 0.002; 2 points), and age < 65 years (OR 3.53; p = 0.008; 1 point). Only 41% of the low-risk group (score 0–1) progressed by 6 months compared to 74% of the intermediate-risk group (score 2) and 91% of the high-risk group (score 3–5). Compared to the low-risk group, the intermediate-risk group had OR for disease progression at 6 months of 4.01 (p = 0.006) and the high-risk group had OR of 15.5 (p < 0.001). Conclusions: We identified risk factors and developed a scoring system that classifies pts. with platinum-refractory UC treated with second-line chemotherapy into risk groups based upon probability of disease progression at 6 months. Similar to the first-line setting, the presence of visceral metastases and decreased KPS predict a worse prognosis. This system should be validated in other independent populations.

[Table: see text]

Ki67 as a prognostic biomarker for patients with vertical growth phase (VGP) melanomas

9043

Background: In VGP melanomas proliferation is reflected in dermal mitotic figures (“mitogenic” VGP) and/or tumor cell nests larger than any epidermal nest. An alternative to mitotic rate (MR) to characterize cell proliferation is the expression of Ki67 protein. Since Ki67 is expressed in all phases of the cell cycle except G0, it is potentially a more robust biomarker for proliferation and prognosis than mitoses. Methods: To test the hypothesis that Ki67 would replace MR as a prognostic factor, we did a retrospective cohort study of 432 patients with Stage I/II primary VGP melanomas who had at least 10 years of follow up. Tissue sections were stained using the monoclonal antibody MIB-1 to Ki67 and the % of positive melanoma cells were evaluated by two readers. ROC curves for Ki67 and MR were computed. Predicted probabilities (PP) of 10-year melanoma-specific death were computed from 3 multivariate logistic regression models, one for each biomarker (Models 1 and 2) and one with both (Model 3), controlling for established melanoma prognostic factors (thickness, gender, anatomic site, ulceration, regression and tumor infiltrating lymphocytes), and compared. Cross-validation was used to assess differences between using Ki67 and using MR including the differences in PP, Brier scores and the misclassification rates. A decision curve analysis was done to assess the clinical net benefit of the two. Results: The areas under the ROC curve (AUCs) for Ki67 and MR, both continuous factors, were 0.69 and 0.79, respectively. In the multivariate analysis, Ki67 expression was significant in Model 1 (OR=1.03, 95% CI: 1.01–1.05), mitotic rate was not significant in Model 2 (1.05, 0.99–1.1), and only Ki67 was significant in Model 3 (1.03, 1.01–1.05). The AUCs for the three models were 0.84, 0.84, and 0.85, respectively. Based on cross-validation, there was no difference between the two biomarkers in PP, Brier scores, or misclassification rates. The decision cost analysis demonstrated the same net benefit for the two. Conclusions: A prospective study needs to be conducted to confirm that Ki67 and MR are equivalent.

No significant financial relationships to disclose.

The prognostic significance of lymphatic invasion in primary melanoma

9050

Background: Lymphatic invasion (LI) is an under-observed phenomenon in primary malignancies that can be better detected by immunostaining and that may associate with prognosis. In this study we sought to test the hypothesis that LI was associated with melanoma-specific survival (MSS) and was an independent prognostic factor. Methods: This study included 277 patients with stage I/II melanomas in vertical growth phase (VGP) who had at least 10 years of follow up. The log-rank test was used to test the study hypothesis - 72 melanoma-specific deaths were needed for 80% power to detect an odds ratio of 2.1. Paraffin sections were stained with antibodies to podoplanin (lymphatic vessels) and S-100 (melanoma cells) to identify LI. Univariate and multivariate Cox models were used to evaluate the prognostic significance of LI. An independent cohort of 106 similar patients was used for validation of the 10-year MSS rates. Results: LI was observed in 44.5% (95% CI: 38.6% - 50.4%) of the melanomas and its presence was significantly associated with thickness, mitotic rate, gender, age, and ulceration (U). The Kaplan-Meier survival curves for those with and without LI were significantly different (log-rank test p=0.022). The final multivariate model for time to MSD identified 4 independent prognostic factors: thickness (HR=1.5, p<0.001), U (HR=2.2 p=0.013), site (HR=3.9, p<0.001) and LI (HR=1.9, p=0.015). These factors were used to define a prognostic tree with 5 risk groups defined by melanomas that were thin (≤1.0mm) with no LI or U; thin with LI but no U; 1–3mm with no U; 1–3mm with U; and >3mm. Respectively, MSS rates were 100%, 88.6%, 77%, 48% and 42%. In the validation set, observed 10-year MSS rates in each risk group were not significantly different from those predicted from the survival curves for the tree-based risk groups. Conclusions: LI is an independent prognostic factor for MSS. Among patients with thin melanomas without U the 10-year MSS was lower for those patients with LI (89%, 95% CI=78% - 99%; n=41) compared to those without (100%, n=78). LI is an important prognostic factor that needs further validation in a population of patients from the sentinel node biopsy era.

No significant financial relationships to disclose.

Comparison of iridium implant boost versus electron boost as a component of breast conservation treatment for early-stage breast carcinoma

Abstract #5144

Background: Breast conservation treatment includes lumpectomy followed by definitive radiation therapy, with radiation delivered to the whole breast followed by tumor bed boost. Currently, the boost is typically delivered by electron beams, but was previously delivered by iridium-192 implants. With re-emergence of implant radiotherapy techniques in current practice, long-term outcomes of both boost techniques are important.&#x2028; Methods: From 1977 to 1983, 141 patients with early-stage breast cancer were treated with iridium-192 boost after whole breast radiation. These patients were matched 1:1 to 141 patients who received electron boost from 1980 to 1990. Most implant patients were treated before widespread electron availability. Matching criteria included age at diagnosis, final pathologic margin status, pathologic tumor stage, and pathologic nodal stage. All patients had AJCC Stage I or II invasive breast carcinoma, had surgical excision of the primary tumor, and underwent definitive radiation to at least 60 grays. Chemotherapy was administered to 30 implant patients and 41 electron patients (p=0.014), and hormonal treatment to 3 implant patients and 12 electron patients (p=0.032). These systemic treatment variations were expected due to treatment era differences. Median follow-up was 16.7 years for implant patients (range 0.7-28.5) and 12.6 years for electron patients (range 1.4-25.4) (p&lt;0.001).&#x2028; Results: Electron boost patients were more likely to have excellent/good cosmesis versus fair/poor cosmesis than implant boost patients. At 1-year follow-up, this was significant (p=0.014). This trend continued, with odds ratio of having excellent/good cosmesis versus fair/poor cosmesis in implant patients compared to electron patients being 0.29 after 5 years (95% CI 0.027-1.38, p=0.114) and 0.24 after 10 years (95% CI 0.005-1.93, p=0.266).&#x2028; Incidence of all complications evaluated did not differ between the two groups (all p≥0.07). Incidence of breast fibrosis was 3% per year in implant patients and 4% per year in electron patients (p=0.17). In total, breast fibrosis developed in 41% of implant patients and 16% of electron patients. Incidence of infection was 14% per year in the implant group and 6% per year in the electron group (p=0.09). In total, infection developed in 7% of implant patients and 9% of electron patients. Incidence of rib fracture was 2% per year in both groups (p=0.8). Incidence of cardiopulmonary complications was 4% per year in implant patients and 3% per year in electron patients (p=0.7). Incidence of non-cardiac vascular complications was 4% per year in both groups (p=0.1). Incidence of neuropathy was 4% per year in implant patients and 1% per year in electron patients (p=0.07).&#x2028; Conclusions: Patients treated with electron boost were more likely than those treated with implant boost to have excellent/good cosmesis, though this observation did not reach statistical significance at 5- and 10-year follow-up. Complication rates did not differ significantly between the groups with long-term follow-up.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5144.