Tumorogenesis and mdm2 protein

Tumorogenesis is associated with several events by which a normal cell tran sforms itself into a tumour cell with an increased proliferation rate. One of the most important research initiatives in this area is the characteriza tion of the molecular mechanisms involved in tumorogenesis and cancer. Onco genes and tumour suppressor genes are directly involved in the cell cycle, differentiation, and apoptosis. The cellular oncogene MDM2 seems to be abno rmally elevated in several human tumours, specially in sarcomas. The MDM2 g ene product, mdm2 protein, pS3 and retinoblastoma (Rb) proteins, play cruci al roles in the control of the cell cycle. The molecular interactions betwe en mdm2, pS3 and Rb in cancer, are associated with a loss of control in the G1 phase of the cell cycle leading to uncontrolled cell proliferation. Stu dies by gene amplification appear to show an incomplete picture of mdm2 pro tein levels in tumour cells. The simultaneous determination of mdm2 protein and mRNA levels seems to give a more accurate interpretation of the abnorm al function of the mdm2 protein. Thus, in addition to gene amplification, d ifferent mechanisms by which mdm2 is overexpressed in cancer cells also pla y an important role in tumorogenesis.