Figure 1

Molecular changes of serous carcinogenesis. Ovarian low-grade serous carcinoma (LG-SC) development starts from tubal epithelia, which invaginate into ovarian stroma to form ovarian epithelial inclusions (OEI). Further growth of OEI forms serous cystadenoma, serous borderline tumor, and LG-SC in a step-wise fashion. The most common molecular changes including KRAS, BRAF, or ERBB2 mutations are increased in this process as indicated in the upper panel. Chromosomal changes are more common prior to the development of LG-SC. In contrast to LG-SC, high-grade serous carcinoma (HG-SC) develops in a different pathway. It starts from tubal epithelia, then develop into latent precancer (p53 signature), precancer (tubal dysplasia), early cancer (serous intraepithelial carcinoma, STIC), and to full blown HG-SC. Within this process, the earliest molecular change is p53 gene mutation as indicated in the low panel. Other molecular changes are included in the figure, too. There are about 10% or less LG-SCs which can develop into HG-SC upon acquiring p53 mutation.