Low frequency of defective mismatch repair in a population-based series of upper urothelial carcinoma

BACKGROUND: Upper urothelial cancer (UUC), i.e. transitional cell carcinomas of the renal pelvis and the ureter, occur at an increased frequency in patients with hereditary nonpolyposis colorectal cancer (HNPCC). Defective mismatch repair (MMR) specifically characterizes HNPCC-associated tumors, but also occurs in subsets of some sporadic tumors, e.g. in gastrointestinal cancer and endometrial cancer. METHODS: We assessed the contribution of defective MMR to the development of UUC in a population-based series from the southern Swedish Cancer Registry, through microsatellite instability (MSI) analysis and immunohistochemical evaluation of expression of the MMR proteins MLH1, PMS2, MSH2, and MSH6. RESULTS: A MSI-high phenotype was identified in 9/216 (4%) successfully analyzed patients and a MSI-low phenotype in 5/216 (2%). Loss of MMR protein immunostaining was found in 11/216 (5%) tumors, and affected most commonly MSH2 and MSH6. CONCLUSION: This population-based series indicates that somatic MMR inactivation is a minor pathway in the development of UUC, but tumors that display defective MMR are, based on the immunohistochemical expression pattern, likely to be associated with HNPCC

Women with familial risk for breast cancer have an increased frequency of aldehyde dehydrogenase expressing cells in breast ductules

BACKGROUND: Knowledge is limited regarding the association between stem cells in histologically benign breast tissue and risk factors for breast cancer, and hence we addressed this issue in the present study. Recently, we assessed the histology of benign breast tissue from cancer and non-cancer patients for cells positive for the putative stem cell marker aldehyde dehydrogenase 1 A1 (ALDH), and the findings indicated an association between expression of ALDH and the hormonal factors menopause and hormone therapy. The current investigation examined possible associations between various known clinical and genetic risk factors for breast cancer and cellular expression of ALDH in ductules in benign human breast tissue.METHODS: The study included breast surgery patients that were BRCA1/2 mutation carriers without breast cancer (n = 23), had BRCA1/2 (n = 28) or sporadic (n = 21) breast cancer, or required non-cancer-related mammoplasty (n = 34). The distribution and frequency of ALDH-immunolabelled cells were correlated to patient subgroups with different risk factors, using mammoplasty patients as a control group. Statistical analyses comprised linear and logistic regression, Spearman's rank test, Pearson's test, and Fisher's exact test. In two-tailed tests, p < 0.05 was considered significant.RESULTS: A strong association was found between family history of breast cancer and a high frequency of ALDH+ cells (p = 0.001) at all ductular levels in all groups, regardless of BRCA status, age, parity, or occurrence of cancer. In pre-menopausal non-BRCA cancer patients, the frequency of ALDH+ cells increased with age (p < 0.01) but decreased with increasing parity (p < 0.03). High frequencies of ALDH+ cells were found in the non-basal ductular levels in BRCA1 mutation carriers (p = 0.03), but in the basal ductular level in BRCA2 cancer patients (p = 0.02). Among post-menopausal patients, only on-going hormone replacement therapy was correlated with a high number of ALDH+ cells (p < 0.03).CONCLUSION: In histologically normal breast tissue, we found a positive association between the frequency of ductular ALDH+ cells and several breast cancer risk factors, particularly family history of this disease, which supports previous evidence that ALDH plays a role in breast cancer