Average labelling indices (LIs) for p16, p21, Rb, cyclin A and cyclin E showed a stepwise increase from astrogliosis, through low- to high-grade astrocytomas, indicating the possibility that over 9%, 6% and 4% of LIs for p16, p21 and cyclin A, respectively, may be useful predictors in the case of the latter, in contrast to significant decrease in p27 LIs.
Moreover, the activation of p27 KIP1 was preserved in the astrocytic tumors and its cytoplasmic manifestation seems to be resultant of its nuclear expression, not demonstrating a direct impact in astrocytomas tumorigenesis.