Expression of Bcl-2 mRNA detected by ISH consistently differed from that detected by IC, especially in lymph node metastases (whereas no relevant variations of Bcl-2 mRNA levels were found in treated vs. untreated CaP patients).
Aneuploidy, oncogene expression (p53, HER-2/neu, bcl-2), and hormone receptors were not significantly related to lymph node metastasis and cancer recurrence.
The high level of apoptotic cell death was associated with negative immunostaining for bcl-2 protein, the loss of estrogen and progesterone receptors, high proportion of cells in S-phase, and increased risk of lymph node metastases.
Bcl-2 expression was strongly associated with both apoptosis loss (pOR, 6.9; trend test, P < 0.0001) and presence of lymph node metastases (pOR, 5.7; trend test, P = 0.002).
Oncogenic control of programmed cell death is therefore important in melanoma progression and bcl-2 measurement provides a useful marker of prognosis for regional lymph node metastases.
The co-expression of PR significantly modified the effect of Bcl-2 on the odds for lymph-node metastasis, suggesting the existence of a synergistic interaction between the 2 parameters.
The retention of BCL-2 expression in the carcinomas and lymph node metastases may explain the resistance of colorectal tumours to chemotherapeutic treatment.