Disruption of cell cycle central by human papillomaviruses with special reference to cervical carcinoma

Human papillomaviruses (HPVs) play a major role in neoplastic transformatio n of squamous epithelial cells. The viral genome is small in size and only encodes a limited number of proteins, so one of the major functions of the viral proteins is to modulate the function of key cellular proteins involve d in cell cycle control and DNA replication. During this process important host cell cycle checkpoints are lost which may lead to the accumulation of genetic abnormalities and eventual malignant transformation. This review br iefly describes the normal cell cycle and also the mechanisms by which HPVs interfere with cell cycle control both as part of their productive life cy cle and in the process of neoplastic transformation.