Apoptosis, analysed by means of lamin B detection, correlates with grade of astroglial tumours but not with p27Kip1/retinoblastoma protein expression

The aim of our study was to correlate apoptosis, assessed by means of lamin B degradation, with grade of tumour and immunohistochemical expression of p27Kip1and retinoblastoma protein (pRB) in a series of 32 low-grade astrocytomas (LGA) and 43 high-grade astrocytomas (HGA). Determination and analysis of lamin B expression was achieved stereologically with the use of computerised interactive image analysis. The average stereological surface density of the lamin-positive nuclear surface of cells showing evidence of lamin degradation cells was 13.80 mm2/mm3in LGA and 21.02 mm2/mm3in HGA. The average range of immunopositivity of p27 and pRB expression was 2.85 and 2.10, respectively, in LGA and 1.80 and 0.88, respectively, in HGA. The rate of apoptosis indirectly correlated with the expression of both p27 and pRB but was not fully significant (P≤0.09). Our findings suggest that there may be a loss of function of main cell-cycle regulators and increased uncontrolled cell death in addition to increased cell proliferation in high-grade astrocytomas. Moreover, we believe that the detection of lamin B degradation in astroglial tumours can be an alternative, precise and convenient assay for the detection of a defined set of apoptotic cells. However, before being applied more generally, comparative research should be done on different methods of quantifying apoptosis, with the intent of finding the difference between biologically different methods. Such studies would also be able to find the method associated with the strongest prognostic power.