Correlation between pathological data and the RNA expression of p53 or p53-targeted genes in primary invasive ductal breast carcinomas: a preliminary study

The protein expression of the growth suppressive p53 transcription factor and its inhibitor human double minute 2 (Hdm2) is altered in ductal breast carcinomas (DBC). However, the assessment of p53 and/or Hdm2 protein levels in DBC tissues was found to have a questionable prognostic significance. We evaluated the RNA expression of p53, hdm2, and the p53-targeted p21waf-1 and thrombospondin (tsp)-1 by primary DBC tissues, then correlated the RNA levels with patient clinicopathological data. The mean RNA expression level of p53 and that of hdm2 were elevated in large-sized, poorly differentiated, node-positive DBC, while a high p21waf-1 or tsp-1 mean expression level comprised small-sized, low-grade, node-negative tumors. Further analyses found that the correlation between the RNA expression of p53 and that of its targeted genes was reduced as tumor aggressiveness increased. However, for all the examined genes, association of the intensity of RNA expression with the pathological data was not statistically significant (p>0.05). Altogether, our preliminary RNA data confirm the results from previous protein studies, indicating that despite p53 expression and activity show a trend to vary in association with DBC clinical features, neither p53 nor its transcriptional targets can accurately monitor the behaviour of invasive DBC.