Two cases of endometrial cancer meeting new clinical criteria for hereditary nonpolyposis colorectal cancer

Effects of tamoxifen on the endometrium and its mechanism of carcinogenicity

This study was conducted to clarify the clinicopathological characteristics of tamoxifen-associated endometrial carcinomas and its mechanisms of carcinogenesis. Seven patients with tamoxifen-associated endometrial carcinomas (TAM group) and 28 with sporadic endometrioid adenocarcinomas (EMC group) were included in the study. The clinicopathological factors, such as FIGO stage, histological type, grade, lymph node metastases, vascular invasion and the coexistence of hyperplasia, were investigated in both groups. The protein expression of p53, PTEN, hMLH1 and hMSH2 was investigated by immunohistochemistry. Microsatellite instability (MSI), k-ras and p53 mutation were also examined. In the TAM group, the histological types included five endometrioid, one endometrioid combined with serous and one clear cell type. The rates of coexistence with hyperplasia (five of seven cases) and vascular invasion (four cases) were significantly higher in the TAM group. The rates of stage III/IV (four cases) and lymph node metastasis (three cases) tended to be higher in the TAM group. Although there were no significant differences in PTEN, hMLH1 and hMSH2 expression between the two groups, p53 mutation was more frequent in three out of five cases (60%) in the TAM group compared with 2 of 15 cases in the EMC group (13.3%). No significant differences were observed concerning MSI and k-ras mutation in either group. These results suggested that TAM-associated endometrial carcinomas have overlapping biological characteristics of type I and type II endometrial carcinomas. This might explain the somewhat worse prognosis of these tumors than sporadic endometrioid carcinomas.

Two Japanese kindreds occurring endometrial cancer meeting new clinical criteria for hereditary non-polyposis colorectal cancer (HNPCC), Amsterdam Criteria II

Hereditary non-polyposis colorectal cancer (HNPCC), also called Lynch syndrome, is an autosomal dominantly inherited disorder of cancer susceptibility. Patients with HNPCC exhibit an increased risk for HNPCC-associated extracolonic tumors such as cancer of the endometrium. HNPCC is associated with germline mutations in DNA mismatch repair (MMR) genes: hMLH1, hMSH2 and hMSH6. Here, we describe two Japanese kindreds (0.5%) who met the new clinical criteria for HNPCC, Amsterdam criteria II, from among 375 endometrial cancer patients treated at Keio University Hospital from 1990 to 2002. From these results, it was found that female HNPCC patients comprised approximately 0.5% of all endometrial cancer patients. Decreased expression of two MMR gene protein products (hMLH1 and hMSH6) was confirmed immunohistochemically in these two endometrial tumors in HNPCC kindreds. This case report provides important information on Japanese HNPCC patients occurring endometrial cancer.