Prostate cancer is the most common cancer among men. Green tea consumption is reported to play an important role in the prevention of carcinogenesis in many types of malignancies, including prostate cancer; however, epidemiological studies show conflicting results regarding these anti-cancer effects. In recent years, in addition to prevention, many investigators have shown the efficacy and safety of green tea polyphenols and combination therapies with green tea extracts and anti-cancer agents in in vivo and in vitro studies. Furthermore, numerous studies have revealed the molecular mechanisms of the anti-cancer effects of green tea extracts. We believe that improved understanding of the detailed pathological roles at the molecular level is important to evaluate the prevention and treatment of prostate cancer. Therefore, in this review, we present current knowledge regarding the anti-cancer effects of green tea extracts in the prevention and treatment of prostate cancer, with a particular focus on the molecular mechanisms of action, such as influencing tumor growth, apoptosis, androgen receptor signaling, cell cycle, and various malignant behaviors. Finally, the future direction for the use of green tea extracts as treatment strategies in patients with prostate cancer is introduced.

BackgroundIn the WHO 2010 classification, the neuroendocrine tumors (NETs) are subdivided by their mitotic index or Ki67 index into either G1 or G2 NETs. Tumors with a Ki67 index of <2% are classified as G1 and those with 3—20% are classified as G2. However, the assessment of tumors with Ki67 index of greater than 2% and less than or equal to 3% is still unclear. To resolve the problem, we validated the Ki67 index criteria of gastrointestinal NETs of the WHO 2010 classification.MethodsThe medical records of 45 patients who were pathologically diagnosed as having NET G1/G2 of the gastrointestinal tract were analyzed retrospectively. According to the WHO 2010 classification, Ki67 index were calculated. Computer-assisted cytometrical analysis of Ki67 immunoreactivity was performed using the WinRooF image processing software. Receiver operating characteristic (ROC) curves were generated to determine the best discriminating Ki67 index. To clarify the assessment of tumors with Ki67 index between 2—3%, the calculated cutoff of Ki67 index was evaluated using Fisher’s exact test.ResultsROC curve analysis confirmed that 2.8% was the best Ki67 index cutoff value for predicting metastasis or recurrence. The sensitivity of the new Ki67 index cutoff was 42.9%, and the specificity was 86.8%.ConclusionsDivision of NETs into G1/G2 based on Ki67 index of 3% was appropriate to predict metastases or recurrences. The WHO grading system may be the most useful classification to predict metastases or recurrences.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1553036118943799

Limited information is available on the pathologic significance of human antigen R (HuR) in prostate cancer (PCa). The main aim of this study was to clarify the relationship between HuR expression and malignant aggressiveness, outcome, and expression of cancer-related molecules in PCa. In vitro proliferation, colony formation, and migration assays were performed on LNCaP and PC-3 cells. HuR expression was knocked down (KD) using small interfering RNA. The relationships between HuR expression and the expression of vascular endothelial growth factors (VEGFs), cyclooxygenase (COX)-2, and heme oxygenase (HO)-1 were investigated in PCa cell lines using Western blotting. On KD of HuR, cell proliferation and migration were suppressed in both LNCaP and PC-3 cells, whereas expression of VEGF-A to -D and COX-2 was suppressed in PC-3 but not in LNCaP cells. In addition, expression of these cancer-related factors was analyzed in 182 hormone-naïve PCa and 23 castration-resistant prostate cancer (CRPC) human tissues in vivo. Cytoplasmic (C)-HuR expression was significantly higher in CRPC > hormone-naïve PCa > nontumoral cells. C-HuR expression was positively associated with Gleason score, T stage, and metastasis, and it was considered to be a useful predictor of biochemical recurrence after radical prostatectomy. C-HuR expression was correlated with COX-2 expression in hormone-naïve PCa, and with the expression of VEGF-A, VEGF-C, and COX-2 in CRPC tissues. Our results demonstrated that HuR plays important roles in determining malignant aggressiveness and outcome in PCa, especially in androgen-independent PCa cells, via the regulation of cell proliferation, migration, and expression of VEGF-A, -C, and COX-2.

DNA intrastrand cross-linking agents such as oxaliplatin induce DNA double-strand breaks (DSBs) during DNA repair and replication. In the present study, we hypothesized that DNA intrastrand cross-linking agents may significantly benefit colorectal cancer patients with deficiencies in DSB repair. Seventy-eight patients with metastatic or recurrent colorectal cancer who had measurable target lesions and who underwent resection for primary colorectal cancer in our institution between April 2007 and March 2013 were included in the present study. The median age was 64.5 years, and the cohort consisted of 49 males and 29 females. The median progression-free survival (PFS) was 10.9 months. The expression of DSB repair proteins such as RAD51 and MRE11 was investigated by immunohistochemistry, and associations between RAD51 and MRE11 expression and clinicopathological factors or chemotherapeutic effect were assessed. MRE11-negative cases and RAD51-negative cases achieved significantly better tumor reduction compared with cases with positive expression. Cases with negative expression of both proteins or negative expression of either protein had significantly longer PFS than cases with positive expression for both proteins. In conclusion, DSB repair protein expression-negative colorectal cancer cases may be more highly sensitive to chemotherapy, and thus DSB repair protein expression may be a useful prognostic indicator for colorectal cancer patients.

A hyperplastic polyp (HP) >10 mm is described as a large hyperplastic polyp (LHP). Previous studies have considered LHP and sessile serrated adenoma/polyp (SSA/P) as synonymous. Although HP and SSA/P have previously been morphologically distinguished, differences between LHP and SSA/P have not yet been reported. The present study aimed to define the differences between SSA/P and non-SSA/P in LHP using immunohistochemistry for Ki67. Colorectal serrated lesions (>10 mm) that were completely resected by endoscope and derived from 11 institutions in Japan [Dokkyo Medical University School of Medicine (Mibu), Takahiro Fujii Clinic (Tokyo), Sano Hospital (Kobe), Oda GI Clinic, Hattori GI Endoscopy and Oncology Clinic (Kumamoto), Ohta Clinic (Nagoya), Hiroshima University (Hiroshima), Iwate Medical University (Morioka), Juntendo and Kyorin Universities (Tokyo) as well as Toyama University (Toyama)] affiliated with the Japanese Society for Cancer of the Colon and Rectum (JSCCR) between January 2003 and December 2010 were selected. The histological criteria of the Japanese Society for Cancer of the Colon and Rectum (JSCCR, project meeting; editor-in chief, Takashi Yao) were used to distinguish SSA/P and non-SSA/P from LHP. Non-SSA/P comprises both incomplete SSA/P and HP. A total of 154 samples diagnosed as SSA/P or non-SSA/P from 148 patients were used. This study comprised 107 SSA/P and 47 non-SSA/P cases, whereby lesions were located on the right side of the colon (73.2 and 26.8%, respectively). Ki67-positivity in SSA/Ps was significantly higher compared to non-SSA/Ps. A greater number of SSA/Ps in LHP were located on the right side of the colon compared to the left side. SSA/Ps occurring on the right side of the colon may be precursor lesions of colorectal carcinoma in serrated neoplasia pathways. In conclusion, LHPs and SSA/Ps limited to the right side of the colon are suggested to be clinically treated as the same type of lesions.