[Peculiarities of regulation of tumour cell apoptosis].

Studies of expression of BCL-2 gene family revealed abnormal regulation of biosynthesis of apoptosis-related proteins in tumour cells involved in the development and progress of neoplastic diseases. Expression of BCL-2 proteins in highly differentiated gastric and colonic tumours was roughly 1.2 times lower than in the normal cells. A 3.5-fold rise in BCL-2 expression was documented in a group of moderately differentiated adenocarcinomas and undifferentiated tumours. The most striking (9-fold) difference between BCL expression in untransformed and atypical cells was recorded in moderately differentiated metastatic colonic adenocarcinoma. Immunohistochemical studies of BAX expression in untransformed and atypical gastric and colonic cells demonstrated activation of apoptosis-inducing mechanisms in the pathologically changed tissue. Investigations with the use of SSCP showed that 20% of the patients had BAX gene mutations affecting codons 38 to 41 of exone 3. This region was found to contain octadeoxyguanosine G8 sequence. The mutations were caused by deletion of G7 or insertion of G9.