Risk of breast cancer recurrence in women initiating tamoxifen with CYP2D6 inhibitors

CRA508

Background: Tamoxifen (TAM) is metabolized to its active form, endoxifen, by hepatic cytochrome P450 (CYP) 2D6. Diminished CYP2D6 function, both by genetic variation or concurrent use of pharmacologic inhibitors, can significantly reduce endoxifen plasma concentrations and may lead to reduced TAM effectiveness. Methods: We interrogated an integrated research database comprised of de-identified medical and pharmacy claims (Rx) data for 10.7 million U.S. health plan members to identify women with breast cancer (BrCa) new to TAM therapy in a 30-month period from 2003 to 2005, and investigated the risk of recurrent BrCa as a function of concurrent use of potent and moderate inhibitors of CYP2D6. Inclusion criteria were: greater than or equal to 24 months of follow-up data and adherence to TAM (medication possession ratio > 70%) over 2 years (N = 1,298). Disease recurrence was defined by BrCa ICD-9 codes or CPT codes for mastectomy, lumpectomy, lymph node dissection, or radiation therapy occurring at least 6 months after the index TAM Rx. Two study groups were identified: TAM alone (N = 945) or TAM + a CYP2D6 inhibitor concomitantly (N = 353). BrCa recurrence rates were compared using Kaplan-Meier analysis with log-rank test, and univariate hazard ratios (HR) with 95% confidence intervals (CI) were estimated by Cox proportional hazards model. Results: The study groups were similar at baseline. Median age was 52 years (TAM) and 53 years (TAM + CYP2D6 inhibitor). Interventions performed in the TAM alone group included mastectomy in 54%, lumpectomy in 36%, and radiation therapy in 47%, and were 52%, 38%, 46%, respectively, in the TAM + CYP2D6 inhibitor group. Among women on a CYP2D6 inhibitor, the median duration of overlap with TAM was 255 days. Patients receiving TAM + a CYP2D6 inhibitor had a 2-year BrCa recurrence rate of 13.9% versus 7.5% in patients receiving TAM alone (HR 1.92, 95% CI 1.33–2.76, p < 0.001). Conclusions: Our findings support the presence of a clinically significant drug interaction between TAM and known CYP2D6 inhibitors. This resulted in a significant 1.9 fold higher BrCa recurrence within 2 years of initiating TAM therapy.

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Resistance mutations in HIV-1 infected pregnant women and their infants receiving antiretrovirals to prevent HIV-1 vertical transmission in China

The objective of this study was to assess the resistance baseline in HIV-1-infected pregnant women in China and the emergence of drug resistance (DR) among them and their infants after receiving single-dose nevirapine (sdNVP) or zidovudine plus sdNVP (ZDV-sdNVP) for the prevention of mother-to-child transmission (PMTCT). The prospective study followed 62 drug-naïve HIV-1-infected mothers and their infants who received sdNVP for PMTCT and 18 who received ZDV-sdNVP. Primary DR was detected in 8.8% (7/80) of pregnant women at baseline. Two (2.5%) women had mutations associated with nucleoside reverse transcriptase inhibitors (NRTI). Six (7.5%) women harboured mutations associated with non-nucleoside reverse transcriptase inhibitors (NNRTI). No protease inhibitor (PI) DR was detected. The DR rates in infected mothers selected by sdNVP and ZDV-sdNVP regimen were 16.3% and 0%, respectively. Women with the emergence of DR after sdNVP had lower CD4 cell counts at delivery than women without DR after sdNVP (178 vs.364 cells/mm(3), P < 0.05). The vertical transmission rate in women with baseline resistance was similar to that in women without baseline resistance (1/7 vs. 3/73, P > 0.05). The study indicates that NVP resistance after sdNVP was associated with CD4 cell count at delivery. ZDV-sdNVP regimen was of more significance in the prevention of the emergence of NNRTI-related DR than sdNVP.

Risk of breast cancer recurrence in women initiating tamoxifen with CYP2D6 inhibitors

CRA508

The full, final text of this abstract will be available in Part II of the 2009 ASCO Annual Meeting Proceedings, distributed onsite at the Meeting on May 30, 2009, and as a supplement to the June 20, 2009, issue of the Journal of Clinical Oncology.

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Inadequate BCR-ABL monitoring in imatinib-treated patients with chronic myelogenous leukemia

7077

Background: Recommendations for baseline and quarterly measurement of the BCR-ABL fusion transcript to monitor imatinib response in patients with chronic myelogenous leukemia (CML) were formally introduced in October 2006, and have been incorporated into nationally recognized treatment guidelines. Methods: To assess BCR-ABL testing rates, we conducted a retrospective cohort analysis using a >10 million-member health plan database comprised of integrated pharmacy and medical claims. The study cohort was defined as patients with an index imatinib pharmacy claim from July 1, 2006, to December 31, 2006, who had a CML diagnosis (ICD-9 205.1X; N = 504), and a minimum of 3 months continuous follow-up by claims history (N = 465). Over a period of up to four quarters from the index imatinib prescription date, BCR-ABL testing in each quarter was assessed by the presence of any of a set of 19 CPT-4 codes. BCR-ABL testing rates in each individual quarter and in consecutive quarters were measured. Results: The overall study cohort was 57% male; mean (±SD) age was 52±14 y/o, with 26% 19–44 y/o, 57% 45–64 y/o, and 15% ≥65 y/o. Median duration of f/u was 559 days (interquartile range 302–628 days), and a cohort of 359 patients had 4 quarters of f/u. At least one BCR-ABL test was recorded in 60% of patients. The rate of first quarter BCR-ABL testing was 40%, and remained at 42%-43% in quarters 2 thru 4. Consecutive quarterly testing rates were 24% through the second quarter, 18% through the third quarter, and 14% through the fourth quarter. Conclusions: In this retrospective claims database analysis, only 14% of a large cohort of CML patients treated with imatinib had BCR-ABL testing recorded in each of 4 consecutive quarters. Inadequate compliance with recommended BCR-ABL testing can delay treatment decisions, and may be associated with poor clinical outcome.

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Electrochemical performance of nanocrystalline SnO2-carbon nanotube composites as anode in lithium-ion cells

SnO2-carbon nanotube composites were prepared by chemical treatment of tin chloride salt mixed with carbon nanotubes, followed by heat-treatment at high temperature. Nanosize SnO2 particles were formed and embedded in a carbon nanotube matrix. TEM and HRTEM observation confirmed the homogeneous distribution of SnO2 nanoparticles. SnO2-carbon nanotube anodes demonstrated high lithium storage capacity and stable cyclability, which could be attributed to the nanosize SnO2 crystals and the formation of carbon nanotube networks in the electrode.

Retrospective analysis of thyroid nodules by clinical and pathological characteristics, and ultrasonographically detected calcification correlated to thyroid carcinoma in South China

OBJECTIVE

To investigate the clinical and pathological characteristics of thyroid nodules, as well as to evaluate the significance of ultrasonographically detected thyroid calcification in the diagnosis of thyroid carcinomas.

METHODS

Retrospective data were studied from 1,051 consecutive patients who underwent a thyroidectomy in the Provincial Hospital of Fujian Medical University in South China between January 2003 and July 2006 for nodular thyroid disease. Complete sonographical information before surgery was only collected from 758 of the 1,051 patients.

RESULTS

Among the 1,051 patients, benign lesions were found in 857 (81.54%) patients, of whom 612 (71.41%) were nodular goiter; malignant lesions were found in 194 (18.46%) patients, in whom benign thyroid lesions were also found in 85 (43.81%) patients. A total of 48 patients suffered from microcarcinomas, of whom 37 patients had benign lesions; these 37 accounted for 43.53 and 77.08%, respectively, of the 85 malignant cases with benign lesions and the 48 cases with microcarcinomas. In the 758 patients who underwent thyroid ultrasonography before surgery, intrathyroidal calcifications were apparent in 243 patients (32.06%). The incidence of calcification was significantly higher in patients with thyroid carcinoma (54.17%) than in those with benign lesions (26.87%; p < 0.005). Detection of calcification in thyroid lesions by ultrasound had a sensitivity of 32.38% and a specificity of 87.35%, with an OR of 3.31 (95% CI, 2.24-4.63), positive likelihood ratio of 2.56, negative likelihood ratio of 0.77 and a kappa value of 0.23.

CONCLUSION

Thyroid carcinoma, especially microcarcinoma, often coexists with benign thyroid disease. Calcification detected by thyroid ultrasound represents a risk factor for malignancy, but is of limited use as a sole marker of malignancy.

Breast tumor evolution

Abstract #PD1-1

Breast tumors are heterogeneous and composed of a variety of cell types with distinct genetic, epigenetic, and phenotypic profiles. However, the molecular basis underlying this intra-tumoral heterogeneity has not been defined. Models that attempt to explain this include the malignant stem cell hypothesis and the genetic diversity combined with clonal selection models. Both of these ideas have been investigated for a long time both in human tumors and in various model systems, leading to the accumulation of numerous findings that are used to support one or the other. Although the two models share some similarities, they explain tumor progression, therapeutic resistance, and recurrence in fundamentally different ways. Increasing data suggest that the cancer stem cell phenotype may just be a consequence of genetic and epigenetic events that occur in tumor cells and that it may change as tumors evolve. Furthermore, there may be differences among tumor types regarding the applicability of the cancer stem cell and clonal evolution models.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr PD1-1.

The effects of asymmetric tonic neck reflex during reaching movement following stroke: preliminary results

Previous studies and clinical observations reveal that stroke survivors show the resurgence of the asymmetric tonic neck reflex (ATNR) both in static and dynamic conditions during maximal efforts. This observation may imply more reliance on the brainstem pathways following stroke. However, the effect of ATNR during a dynamic condition that represents more natural movement, such as reaching, has not been studied before. During reaching movements, the application of a robot controlled haptic environment is important to quantify the effect of ATNR following stroke. Therefore, this paper reports the use of a novel setup using the ACT(3D) robotic device to investigate and quantify this reflexive behavior. Our preliminary results demonstrate that the effect of ATNR is significant in the stroke population when abducting the shoulder at 25% of maximum ability. These results show that the ATNR affects reaching distance especially when shoulder loading in abduction is required. In conclusion, these preliminary results provide evidence that the effect of ATNR in stroke subjects during reaching task can be quantified by using a novel 3-D robotic setup.

Blockade of SDF-1/CXCR4 signalling inhibits pancreatic cancer progression in vitro via inactivation of canonical Wnt pathway

Extra-pancreatic metastasis is a difficult problem for surgical intervention in pancreatic cancer. CXC chemokine receptor 4 (CXCR4) was considered to have an important role in this process. We hypothesized it may contribute to the pancreatic cancer progression through influencing canonical Wnt pathway. The purpose of this study was to examine the functional role of CXCR4 in the progression of pancreatic cancers and explore the possible mechanism. To this end, the relation between CXCR4 and clinical characteristics was analysed. shRNA against CXCR4 was applied to disrupt the SDF-1/CXCR4 signal transduction pathways in pancreatic cancer cell lines. Our results showed that overall survival in the case of patients positive for CXCR4 expression was significantly lower than that in the case of patients negative for CXCR4 expression. Notably, in vitro studies we observed that the abrogation of CXCR4 could obviously influence the pancreatic cancer cell phenotype including cell proliferation, colony formation, cell invasion and also inhibit the TOPflash activity. In addition, Wnt target genes and mesenchymal markers such as Vimentin and Slug were also inhibited in CXCR4 knockdown cells. Collectively, these data reported here demonstrate CXCR4 could modulate the canonical Wnt pathway and perhaps be a promising therapeutic target for pancreatic cancer progression.

Quantitative assessment of first-pass perfusion of oesophageal squamous cell carcinoma using 64-section MDCT: initial observation

AIM

To clarify the feasibility of first-pass perfusion computed tomography (CT) using 64-section multidetector CT (MDCT) for tumour microcirculation of oesophageal squamous cell carcinoma, and to determine the threshold value of first-pass perfusion values for the discrimination between the microcirculation of the tumour and normal oesophagus.

MATERIALS AND METHODS

Forty-one patients with pathologically confirmed oesophageal squamous cell carcinomas served as the test group, which was subdivided into subgroups according to the pathological grades or the status of lymph node metastasis. Forty patients with a normal oesophagus served as controls. All patients underwent volume-based perfusion imaging using 64-section MDCT. Perfusion parameters including perfusion (PF), peak enhancement (PE), blood volume (BV), and time to peak (TTP) were measured. The differences in perfusion parameters between the test and control groups, and between the subgroups were compared statistically. The cut-off values were obtained statistically to discriminate microcirculation between the tumour and normal oesophagus.

RESULTS

Mean values for the BV and TTP of the tumour were 12.57+/-5.15 ml/100g (range 2.9-25.6) and 33.71+/-14.12 s (range 6-65), respectively. Mean values for the BV and TTP of the normal oesophagus were 4.33+/-3.6 ml/100 g (range 0.3-11.7) and 24.15+/-11.67 s (range 6-48), respectively. The BV and TTP were statistically higher in the test group than in the control group (p<0.05), but no statistical differences in the PF and PE were found between the test and control groups (p>0.05). There were no statistical differences in all parameters between the subgroups of pathological grades, and between subgroups with and without lymph-node metastases (p>0.05). For the discrimination of microcirculation of the tumour from that of the normal oesophagus, a threshold BV value of 6.65 ml/100g was determined and achieved a sensitivity of 95.1%, and specificity of 90%.

CONCLUSION

The first-pass perfusion technique using 64-section MDCT could be valuable to assess the microcirculation of oesophageal squamous cell carcinomas.

Are progenitor cells pre-programmed for sequential cell cycles not requiring cyclins D and E and activation of Cdk2?

OBJECTIVES

Based on studies of unicellular organisms or cultured mammalian cells, the generally accepted model of cell-cycle regulation has been developed in which sequential (scheduled) expression of cyclins D, E, A and B and activation of Cdk2 and Cdk1 takes place. It is assumed that the same model is applicable both in vivo and in vitro.

MATERIALS AND METHODS

In the present study, we compared proliferating marrow cells freshly isolated from healthy individuals with proliferating lymphocytes in cultures.

RESULTS

We demonstrate that during progression of freshly collected human bone marrow cells through G(1), S and G(2)/M, only Cdk1 combined with cyclins A and B(1) was distinctly present and active, and its activity gradually increased. In contrast, in vitro growing mitogen-stimulated lymphocytes had perfectly scheduled sequential expression of all four cyclins and Cdk1 and Cdk2 activities.

CONCLUSION

Our findings demonstrate that the pattern of cyclin expression and Cdk activity in bone marrow in vivo is distinctly different from the one observed for normal cells in vitro. Because proliferating bone marrow cells are predominantly expanding populations of committed progenitors, it is likely that during the expansion phase their cell-cycle progression is pre-programmed, being driven solely by Cdk1 combined either with cyclin A or with cyclin B(1). Expansion of progenitor cells thus may not require the early steps of cell-cycle regulation, associated with triggering progression by availability of growth factors and mitogens.

The mitotic checkpoint kinase NEK2A regulates kinetochore microtubule attachment stability

Loss or gain of whole chromosome, the form of chromosome instability commonly associated with cancers is thought to arise from aberrant chromosome segregation during cell division. Chromosome segregation in mitosis is orchestrated by the interaction of kinetochores with spindle microtubules. Our studies show that NEK2A is a kinetochore-associated protein kinase essential for faithful chromosome segregation. However, it was unclear how NEK2A ensures accurate chromosome segregation in mitosis. Here we show that NEK2A-mediated Hec1 (highly expressed in cancer) phosphorylation is essential for faithful kinetochore microtubule attachments in mitosis. Using phospho-specific antibody, our studies show that NEK2A phosphorylates Hec1 at Ser165 during mitosis. Although such phosphorylation is not required for assembly of Hec1 to the kinetochore, expression of non-phosphorylatable mutant Hec1(S165) perturbed chromosome congression and resulted in a dramatic increase in microtubule attachment errors, including syntelic and monotelic attachments. Our in vitro reconstitution experiment demonstrated that Hec1 binds to microtubule in low affinity and phosphorylation by NEK2A, which prevents aberrant kinetochore-microtubule connections in vivo, increases the affinity of the Ndc80 complex for microtubules in vitro. Thus, our studies illustrate a novel regulatory mechanism in which NEK2A kinase operates a faithful chromosome attachment to spindle microtubule, which prevents chromosome instability during cell division.

Decolorization of C.I. Reactive Yellow 84 in aqueous solution by electrocoagulation enhanced with ozone: influence of operating conditions

We studied the use of a combination of electrocoagulation (EC) and ozonation for the decolorization of the azo dye, C.I. Reactive Yellow 84 (RY84). The effects of initial dye concentration, initial pH, current density, salt concentration, ozone flow rate, temperature and interelectrode distance on the decolorization of RY84 were investigated. The results showed that a synergistic effect was achieved by combining EC with ozone for the decolorization of RY84. Under the experimental conditions, the decolorization rate increased with an increase in current density. However, the decolorization rate decreased with an increase in initial dye concentration and salt concentration. The interelectrode distance did not substantially affect the decolorization rate. Other operating parameters such as initial pH, ozone flow rate and temperature had both positive and negative effects. Over 97% of the color decay was achieved within 10 min reaction time under reasonable experimental conditions. When the decolorization of RY84 was complete, the efficiency of removal of total organic carbon (TOC) was more than 85%.