Comparison of p53 gene abnormalities in bilateral and unilateral breast cancer.
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).


CONCLUSIONS
These findings indicate that the genetic changes and mechanism of carcinogenesis in bilateral and unilateral breast cancer are different.
Kinoshita
T
T
Department of Surgery, School of Medicine, Keio University, Tokyo, Japan.
Ueda
M
M
Enomoto
K
K
Ikeda
T
T
Kikuchi
K
K
Ishii
S
S
Kitajima
M
M
D000328:Adult; D000368:Aged; D001483:Base Sequence; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D004273:DNA, Neoplasm / Q000235:genetics*; D005260:Female; D016158:Genes, p53 / Q000235:genetics*; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D018807:Polymorphism, Single-Stranded Conformational
D004273:DNA, Neoplasm