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Expression of p21 and mutant p53 gene products in residual prostatic tumor cells after radical radiotherapy
Author(s) -
Ljung G.,
Egevad L.,
Norberg M.,
Holmberg L.,
Nilsson S.,
Busch C.
Publication year - 1997
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/(sici)1097-0045(19970701)32:2<99::aid-pros4>3.0.co;2-a
Subject(s) - prostate , cancer research , immunohistochemistry , pathology , medicine , cell cycle , staining , biology , cancer
BACKGROUND In a previous study, sextant core biopsies revealed residual tumor in the prostate in 37/55 investigated patients, with an average of 6.8 years after external beam radiation therapy (RRT). More than half of the biopsies exhibited Ki‐67 and PCNA proliferation activity. METHODS The present study aims at further characterizing residual tumor cells post‐RRT by investigating whether the tumor cells exhibit immunohistochemical expression of p21 and mutant p53 gene products, which reflect the state of cell cycle regulatory mechanisms. RESULTS Positive p53 staining was observed in 11% and p21 positivity in 47% of biopsies. The proportion of positively stained cells was low for both antigens. The staining patterns point to the existance of wild‐type p53‐dependent, as well as alternative pathways for p21 protein induction. CONCLUSIONS A low proportion of tumor cells exhibited p53 protein accumulation post‐RRT. G1 arrest, as assessed by p21 immunoexpression, was demonstrated in a low percentage of tumor cells in <50% of post‐RRT biopsies, indicating that the vast majority of residual tumor cells following RRT escape the G1/S checkpoint control and propagate into S‐phase, presumably with a maintained malignant potential. Prostate 32:99–105, 1997. © 1997 Wiley‐Liss, Inc.