p53 Protein Overexpression and p53 Mutations in Invasive Breast Carcinomas Comparison to lymph node status, DNA ploidy and histologic grade

ABSTRACT

Functional loss of the tumor suppressor gene p53 is one of the most frequently detected and diffusely distributed findings among human cancers. Their mutant protein products or point mutations can be detected through immunohistochemistry(IHC) or polymerase chain reaction and single stranded conformational polymorphism(PCR-SSCP). Evaluation of the DNA content of the tumor cell by flow cytometry(FCM) can provide indirect evidence of the functional loss of p53, because the spindle checkpoint in the mitotic phase depends on p53. To evaluate the correlation between p53 mutation and the status of lymph node metastasis or the histological grade of the tumor cell, IHC, SSCP, and FCM in the same tissue was performed from 43 patients of human breast cancer. The results obtained are as follows; 1. Functional loss of p53 was detected in 81.4% of the breast cancer cases by using triple tests and 58.1% at the cases by double test(IHC and SSCP). Positive rates by single test were 41.8% by IHC, 44.2% by SSCP, and 58.1% by FCM. 2. For breast carcinomas no correlation between lymph-node metastasis and the functional loss of p53 detected by IHC or SSCP. 3. The correlation between the functional loss of p53 detected by IHC or SSCP and the aneuploidy of the tumor cells was statistically significant. 4. The triple tests revealed a functional loss of p53 in all cases of grade III breast cancer.