膀胱癌におけるLaser scanning cytometryによるDNA ploidyの解析 : p53タンパクの過剰発現と7番染色体の異数性との関係について

Abstract

膀胱癌においてp53タンパクの過剰発現と染色体7番の異常, ならびにDNA aneuploidyに相関を認めた.したがってp53の異常が染色体数の異常にかかわっている可能性があると考える

The cellular DNA content of certain malignancies is regarded as a prognostic parameter. The mutant p53 is thought to destabilize centrosome replication, which leads to aberrant mitosis and chromosome instability. We investigated the relationship among DNA ploidy pattern type, numerical aberrations of chromosome 7 and p53 overexpression in 20 transitional cell carcinomas of the urinary bladder. The DNA ploidy pattern type was determined by laser scanning cytometry, while p53 overexpression was investigated immunohistochemically. Using fluorescence in situ hybridization with chromosome-specific probes, the copy number of chromosome 7 was counted by touch preparations of interphase nuclei. The cytometric analysis revealed that the DNA patterns were highly correlated with both the numerical aberrations of chromosome 7 (p = 0.0002) and the overexpression of p53. The incidences of p53 overexpression in DNA aneuploid tumors and DNA diploid ones were 78% and 10%, respectively (p = 0.0017). Our results suggest that the overexpression of abnormal p53 protein induces DNA aneuploidy in bladder cancer.