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Background. The results of recent studies have suggested that p53 gene abnormalities are associated with carcinogenesis in several neoplasms. It is believed that bilateral breast carcinomas develop as a result of a different carcinogenetic mechanism and genetic environment from those of unilateral lesions. Methods. p53 Gene abnormalities in bilateral primary breast cancer were detected by polymerase chain reaction-single strand comformation polymorphism (PCR-SSCP) analysis. A total of 76 paraffin embedded tissue specimens from 38 patients with bilateral primary breast cancer were examined, and 62 patients with unilateral breast cancer were analyzed as control subjects. The bilateral tumors were defined as primary, based on clinical parameters and the presence of an intraductal component. There were 13 patients with synchronous bilateral breast cancer and 25 with metachronous bilateral breast cancer. Results. p53 Gene abnormalities were detected in 50% of the bilateral and 25.8% of the unilateral cases, and the difference was significant (P < 0.01, chi-square test). Abnormalities were detected in 56% of the metachronous cases, representing a much higher incidence than that of the unilateral cases (P < 0.001, chi-square test). The incidence of p53 gene abnormalities in the first and second tumors of the metachronous cases was 44% and 68%, respectively. The percentage of patients with a p53 gene abnormality and positive family history was higher for those with bilateral than with unilateral breast cancer (P < 0.01, chi-square test). Conclusion. These findings indicate that the genetic changes and mechanism of carcinogenesis in bilateral and unilateral breast cancer are different.

Background. Sialyl Lewisa antigen (SLA) is considered to be a cancer-associated carbohydrate antigen. Methods. A total of 309 surgically resected primary colorectal cancer specimens and 501 associated metastases to regional lymph nodes were analyzed immunohistochemically using a monoclonal antibody (NS19-9) recognizing SLA. The specimens were obtained from 1981 to 1988 at the Department of Surgery, Keio University 1 School of Medicine (Tokyo, Japan). Results. Sialyl Lewisa antigen expression was detected in 75.4% (233/309) of the primary tumors and in 78.5% (99/126) of the metastases to regional lymph nodes. Significantly stronger expression was noted in the regional lymph node metastases than in the primary lesions (P = 4.5E−7). Sialyl Lewisa antigen expression in the primary tumors correlated significantly with regional lymph node metastasis (P < 0.005), recurrence (P < 0.005), S and postoperative survival (P < 0.001) as determined by univariate analysis. Sialyl Lewisa antigen expression in the regional lymph node metastases also correlated strongly with recurrence (P < 0.005) and survival (P < 0.01). As determined by multivariate analysis, SLA expression in the primary tumor correlated strongly with recurrence (P = 3.0E−6) and survival (P = 6.9E−3). Conclusions. Sialyl Lewisa antigen expression in primary tumors and metastases to regional lymph nodes is a useful marker for evaluating tumor aggressiveness and prognosis in patients with advanced colorectal cancer.