Ogawa et al. (1993) reported that cell kinetics is related to the biological behavior of many tumor types, and they noticed in their study that myoepitheliomas made up of fusiform, epithelioid and clear cells have greater rates of PCNA cells when compared to the plasmocytoid type, thus confirming the low prolipherative activity in this type. The gene discussed is PCNA; the disease is neoplasm.