While a key step in the development of high-grade serous ovarian cancer (HGSOC) - the most common and lethal subtype - is thought to be TP53 gene mutations that cause protein stabilization in the fallopian tube, accumulating evidence suggests that alterations in PTEN expression may be involved in the early stages of serous ovarian cancer development, similar to endometrioid endometrial cancer (72, 73). This evidence concerns the gene PTEN and ovarian serous adenocarcinoma.