Dense sequencing of an ovarian cancer identifies founder non-coding mutations.
Fallopian tube SOX2 overexpression is a common premalignant feature in ovarian cancer.
The expression of SOX2 and MYC in the fallopian tube appears mutually exclusive.
A major obstacle for effective early detection of ovarian cancer is that CA125 and ultrasound can only detect established ovarian cancer. Currently proposed pre-cancer lesions are not amenable to clinical detection because they affect only a small number of cells. In this work we demonstrated that pre-cancer SOX2 overexpression in the FTE is nearly ubiquitous in HGSOCs and is also a common feature in women with BRCA1 and BRCA2 mutations prior to ovarian cancer initiation. Thus, our data has important implications for screening, although it will need additional clinical evaluation to test the feasibility of quantitative detection of SOX2 expression or the expression of its downstream targets for this purpose.