BRAF and ovarian carcinoma: Studies also demonstrated that the overexpression of cyclin D1 has close relationship with low-grade ovarian carcinomas, which is consistent with the view that cyclin D1 is a downstream target of active MAPK (mitogen-activated protein kinase) constitutively expressed in most low-grade ovarian tumors as a results of frequent activating mutations in KRAS (v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog) and BRAF (v-raf murine sarcoma viral oncogene homolog B1) [10-12].