Defective apoptosis as potential mechanism in the tumorogenesis of myelolipoma

Apoptosis is considered an important mechanism of selective deletion that occurs during hematopoiesis. Myelolipoma is a rare benign tumor composed of adipose tissue and hematopoietic cells. The pathogenesis of this benign tumor is still unclear. Analysing the structural levels and apoptosis of normal human bone marrow (NHBM) and human myelolipoma (HM), the apoptotic events resulted abundantly present in NHBM compared to HM, which showed a small number of apoptotic cells. By contrast, Fas expression was strongly present both in NHBM and HM. These findings suggest that an altered function of Fas in myelolipoma is not able to trigger the apoptotic machinery. In conclusion, we hypothesize that drastic reduction of apoptosis in myelolipoma can be considered one of the growth regulatory mechanisms.