Tomoya Yokota

BRAF mutation is a powerful prognostic factor in advanced and recurrent colorectal cancer

Background:Activating mutation of KRAS and BRAF are focused on as potential prognostic and predictive biomarkers in patients with colorectal cancer (CRC) treated with anti-EGFR therapies. This study investigated the clinicopathological features and prognostic impact of KRAS/BRAF mutation in advanced and recurrent CRC patients.Method:Patients with advanced and recurrent CRC treated with systemic chemotherapy (n=229) were analysed for KRAS/BRAF genotypes by cycleave PCR. Prognostic factors associated with survival were identified by univariate and multivariate analyses using the Cox proportional hazards model.Results:KRAS and BRAF mutations were present in 34.5% and 6.5% of patients, respectively. BRAF mutated tumours were more likely to develop on the right of the colon, and to be of the poorly differentiated adenocarcinoma or mucinous carcinoma, and peritoneal metastasis. The median overall survival (OS) for BRAF mutation-positive and KRAS 13 mutation-positive patients was 11.0 and 27.7 months, respectively, which was significantly worse than that for patients with wild-type (wt) KRAS and BRAF (40.6 months) (BRAF; HR=4.25, P<0.001, KRAS13; HR=2.03, P=0.024). After adjustment for significant features by multivariate Cox regression analysis, BRAF mutation was associated with poor OS (HR=4.23, P=0.019).Conclusion:Presence of mutated BRAF is one of the most powerful prognostic factors for advanced and recurrent CRC. The KRAS13 mutation showed a trend towards poor OS in patients with advanced and recurrent CRC.

Histone deacetylase inhibitors activate INK4d gene through Sp1 site in its promoter.

Histone deacetylase (HDAC) inhibitors are known to arrest human tumor cells at the G1 phase of the cell cycle and activate the cyclin-dependent kinase inhibitor, p21WAF1/Cip1. However, several studies have suggested the existence of a p21WAF1/Cip1-independent molecular pathway. We report here that HDAC inhibitors activate a member of the INK4 family, the INK4d gene, causing G1 phase arrest, in the human T cell leukemia cell line, Jurkat. One of the major Trichostatin A (TSA)-responsive elements is a specific Sp1 binding site in the INK4d promoter. Electrophoretic mobility-shift assay revealed that Sp1 and Sp3 can specifically interact with this Sp1 binding site. Furthermore, using chromatin immunoprecipitation assay, we demonstrated that HDAC2 was present in the INK4d proximal promoter region in the absence, but not the presence, of TSA. Taken together, these results suggest that treatment with TSA transcriptionally activates INK4d by releasing HDAC2 from the histone–DNA complex at the INK4d promoter. Using a p21WAF1/Cip1-deleted human colorectal carcinoma cell line, HCT116 p21 (−/−), we show that upregulation of p19INK4d by TSA is associated with inhibition of cell proliferation. Moreover, mouse embryo fibroblasts lacking Ink4d were resistant to the growth inhibitory effects of TSA as compared to their wild-type counterpart. Our findings suggest that p19INK4d in addition to p21WAF1/Cip1 is an important molecular target of HDAC inhibitors inducing growth arrest.

Sesamin, a lignan of sesame, down‐regulates cyclin D1 protein expression in human tumor cells

Sesamin is a major lignan constituent of sesame and possesses multiple functions such as antihypertensive, cholesterol‐lowering, lipid‐lowering and anticancer activities. Several groups have previously reported that sesamin induces growth inhibition in human cancer cells. However, the nature of this growth inhibitory mechanism remains unknown. The authors here report that sesamin induces growth arrest at the G1 phase in cell cycle progression in the human breast cancer cell line MCF‐7. Furthermore, sesamin dephosphorylates tumor‐suppressor retinoblastoma protein (RB). It is also shown that inhibition of MCF‐7 cell proliferation by sesamin is correlated with down‐regulated cyclin D1 protein expression, a proto‐oncogene that is overexpressed in many human cancer cells. It was found that sesamin‐induced down‐regulation of cyclin D1 was inhibited by proteasome inhibitors, suggesting that sesamin suppresses cyclin D1 protein expression by promoting proteasome degradation of cyclin D1 protein. Sesamin down‐regulates cyclin D1 protein expression in various kinds of human tumor cells, including lung cancer, transformed renal cells, immortalized keratinocyte, melanoma and osteosarcoma. Furthermore, depletion of cyclin D1 protein using small interfering RNA rendered MCF‐7 cells insensitive to the growth inhibitory effects of sesamin, implicating that cyclin D1 is at least partially related to the antiproliferative effects of sesamin. Taken together, these results suggest that the ability of sesamin to down‐regulate cyclin D1 protein expression through the activation of proteasome degradation could be one of the mechanisms of the antiproliferative activity of this agent. (Cancer Sci 2007; 98: 1447–1453)

p15INK4b in HDAC inhibitor‐induced growth arrest

Histone deacetylase (HDAC) inhibitors arrest human tumor cells at the G1 phase of the cell cycle and activate the cyclin‐dependent kinase inhibitor, p21WAF1/Cip1. However, several studies have suggested the existence of a p21WAF1/Cip1‐independent molecular pathway. We report here that HDAC inhibitors, trichostatin A (TSA) and sodium butyrate, activate the p15INK4b gene, a member of the INK4 gene family, through its promoter in HaCaT cells. Furthermore, we show that up‐regulation of p15INK4b by TSA is associated with cell growth inhibition of HCT116 p21 (−/−) cells. Our findings suggest that p15INK4b is one of the important molecular targets of HDAC inhibitors.

Neutropaenia as a prognostic factor in metastatic colorectal cancer patients undergoing chemotherapy with first-line FOLFOX

We retrospectively analysed 153 patients with metastatic colorectal cancer who received FOLFOX with or without bevacizumab as first-line chemotherapy. Several background characteristics and chemotherapy features (grade of neutropaenia, use of bevacizumab or irinotecan, re-introduction of FOLFOX, and tumour progression) as time-varying covariates were analysed as potential prognostic factors. Of the 153 patients, mild neutropaenia (grade 1-2) occurred in 60 patients (39%) and severe neutropaenia (grade 3-4) occurred in 46 patients (30%). The other 47 patients (31%) did not experience neutropaenia. According to a multivariate Cox model with time-varying covariates, hazard ratios (HRs) of death were 0.55 (95% confidence interval (CI), 0.31-0.98; P=0.044) for patients with mild neutropaenia and 0.35 (95% CI, 0.18-0.66; P=0.002) for those with severe neutropaenia. Both mild and severe neutropaenia during chemotherapy are associated with improved survival in patients with MCRC. Prospective trials are required to assess whether dosing adjustments based on neutropaenia may improve chemotherapy efficacy.

Meta-analysis of neutropenia or leukopenia as a prognostic factor in patients with malignant disease undergoing chemotherapy.

PurposeWe performed a systematic review and meta-analysis to determine the impact of neutropenia or leukopenia experienced during chemotherapy on survival.MethodsEligible studies included prospective or retrospective analyses that evaluated neutropenia or leukopenia as a prognostic factor for overall survival or disease-free survival. Statistical analyses were conducted to calculate a summary hazard ratio and 95% confidence interval (CI) using random-effects or fixed-effects models based on the heterogeneity of the included studies.ResultsThirteen trials were selected for the meta-analysis, with a total of 9,528 patients. The hazard ratio of death was 0.69 (95% CI, 0.64–0.75) for patients with higher-grade neutropenia or leukopenia compared to patients with lower-grade or lack of cytopenia. Our analysis was also stratified by statistical method (any statistical method to decrease lead-time bias; time-varying analysis or landmark analysis), but no differences were observed.ConclusionsOur results indicate that neutropenia or leukopenia experienced during chemotherapy is associated with improved survival in patients with advanced cancer or hematological malignancies undergoing chemotherapy. Future prospective analyses designed to investigate the potential impact of chemotherapy dose adjustment coupled with monitoring of neutropenia or leukopenia on survival are warranted.

Heavy smoking history interacts with chemoradiotherapy for esophageal cancer prognosis: A retrospective study

Smoking is a well‐known risk factor for esophageal cancer. However, there are few reports that directly evaluate smoking as a prognostic factor for esophageal cancer. Moreover, scarce evidence is available on whether smoking interacts with major treatment modalities of esophageal cancer. In this study we retrospectively analyzed 364 patients with esophageal squamous cell cancer who were treated between 2001 and 2005 at our institution. Background characteristics, including smoking history, were analyzed as potential prognostic factors. Of the 363 patients, 76 patients (20.9%) were non‐smokers or light smokers (non‐heavy), whereas 287 patients (79.1%) were heavy smokers. The 5‐year survival rate for non‐heavy smokers and heavy smokers was 61.8% (95% confidence interval [CI]: 49.1–72.2) vs 44.6% (95% CI: 38.2–50.9), respectively. In a multivariate Cox model (adjusted for age, gender, performance status, alcohol consumption, histology, tumor length, International Union Against Cancer [UICC] stage, and treatment), the hazard ratio for heavy smokers in comparison with non‐heavy smokers was 1.73 (95% CI: 1.12–2.68; P = 0.013). When we stratified by treatment method, heavy smoking was significantly associated with poor survival only in patients treated by chemoradiotherapy (hazard ratio, 2.43; 95% CI: 1.38–4.27; P = 0.002). More importantly, a statistically significant interaction between heavy smoking history and treatment modality was observed (P = 0.041). Our results indicated that smoking history is strongly associated with poor prognosis in patients with esophageal cancer, especially those treated by chemoradiotherapy. Further investigation is warranted to explain this different prognosis.

Neutropenia as a prognostic factor in advanced gastric cancer patients undergoing second-line chemotherapy with weekly paclitaxel

BACKGROUND Neutropenia during chemotherapy has been reported to be a predictor of better survival in patients with several types of cancers, although there are no reports in pretreated patients. METHODS We retrospectively analyzed 242 patients with advanced gastric cancer (AGC) who received weekly paclitaxel (Taxol) as second-line chemotherapy. Background characteristics and neutropenia as time-varying covariates (TVCs) were analyzed as prognostic factors. RESULTS Of the 242 patients, mild neutropenia (grades 1-2) occurred in 101 patients (41.7%) and severe neutropenia (grades 3-4) occurred in 63 patients (26.0%). The other 78 patients (32.2%) did not experience neutropenia. According to a multivariate Cox model with neutropenia as a TVC, hazard ratios of death were 0.61 [95% confidence interval (CI) 0.43-0.85; P = 0.004] for patients with mild neutropenia and 0.61 (95% CI 0.41-0.88; P = 0.009) for those with severe neutropenia. Among the patients in landmark analysis (landmark of 2.5 months; median time to treatment failure of paclitaxel), mild and severe neutropenia remained significant prognostic factors. CONCLUSIONS Our results indicate that neutropenia during chemotherapy is associated with improved survival in patients with AGC who received weekly paclitaxel as second-line chemotherapy. Prospective trials are required to assess whether dosing adjustments based on neutropenia may improve chemotherapy efficacy.

Folate intake along with genetic polymorphisms in methylenetetrahydrofolate reductase and thymidylate synthase in patients with advanced gastric cancer.

Background: A relationship between dietary folate intake and efficacy of fluorouracil (FU) is supported by preclinical data. Furthermore, there are several reports that evaluated genetic polymorphisms of MTHFR (methylenetetrahydrofolate reductase) or TYMS (thymidylate synthase) and efficacy of FU. However, to our knowledge, there are no reports that evaluate simultaneously the effects of folate intake and genetic polymorphisms on clinical outcome of gastric cancer patients. Methods: We retrospectively analyzed the survival impact of estimated folate intake by a food frequency questionnaire and MTHFR and TYMS polymorphisms in 132 patients with advanced gastric cancer who were treated with first-line FU-based chemotherapy. Results: Median overall survival was 11.3 months (95% confidence interval, 9.4-13.4 mo) and median progression-free survival was 5.2 months (95% confidence interval, 4.1-6.3 mo). Patients with folate intake of >260 μg/day (n = 88) showed longer overall survival compared with low folate intake (n = 44; overall survival, 12.2 versus 8.4 mo). In a multivariate Cox model, patients who had folate intake of >260 μg/day, MTHFR 677 TT polymorphism, and TYMS-3′ untranslated region 6-bp insertion were associated with better survival. Similar tendency was observed in progression-free survival. No interaction was observed between folate intake and favorable genotypes. Conclusion: Folate intake and genetic polymorphisms of MTHFR and TYMS were associated with better clinical outcome by FU-based chemotherapy in advanced gastric cancer. Impact: Our results suggested folate intake and folate-related genetic polymorphisms may play an important role in efficacy of FU-based chemotherapy in advanced gastric cancer. Cancer Epidemiol Biomarkers Prev; 19(5); 1311–9. ©2010 AACR.

Prognostic Impact of the 6th and 7th American Joint Committee on Cancer TNM Staging Systems on Esophageal Cancer Patients Treated With Chemoradiotherapy

PURPOSE The new 7th edition of the American Joint Committee on Cancer TNM staging system is based on pathologic data from esophageal cancers treated by surgery alone. There is no information available on evaluation of the new staging system with regard to prognosis of patients treated with chemoradiotherapy (CRT). The objective of this study was to evaluate the prognostic impact of the new staging system on esophageal cancer patients treated with CRT. METHODS AND MATERIALS A retrospective review was performed on 301 consecutive esophageal squamous cell carcinoma patients treated with CRT. Comparisons were made of the prognostic impacts of the 6th and 7th staging systems and the prognostic impacts of stage and prognostic groups, which were newly defined in the 7th edition. RESULTS There were significant differences between Stages I and III (p < 0.01) according to both editions. However, the 7th edition poorly distinguishes the prognoses of Stages III and IV (p = 0.36 by multivariate analysis) in comparison to the 6th edition (p = 0.08 by multivariate analysis), although these differences were not significant. For all patients, T, M, and gender were independent prognostic factors by multivariate analysis (p < 0.05). For the Stage I and II prognostic groups, survival curves showed a stepwise decrease with increase in stage, except for Stage IIA. However, there were no significant differences seen between each prognostic stage. CONCLUSIONS Our study indicates there are several problems with the 7th TNM staging system regarding prognostic factors in patients undergoing CRT.