Evan W Gibbard

Single cell transcriptomes of normal endometrial derived organoids uncover novel cell type markers and cryptic differentiation of primary tumours

AbstractEndometrial carcinoma, the most common gynaecological cancer, develops from endometrial epithelium which is composed of secretory and ciliated cells. Pathologic classification is unreliable and there is a need for prognostic tools. We used single cell sequencing to study organoid model systems derived from normal endometrial endometrium to discover novel markers specific for endometrial ciliated or secretory cells. A marker of secretory cells (MPST) and several markers of ciliated cells (FAM92B, WDR16, and DYDC2) were validated by immunohistochemistry on organoids and tissue sections. We performed single cell sequencing on endometrial and ovarian tumours and found both secretory‐like and ciliated‐like tumour cells. We found that ciliated cell markers (DYDC2, CTH, FOXJ1, and p73) and the secretory cell marker MPST were expressed in endometrial tumours and positively correlated with disease‐specific and overall survival of endometrial cancer patients. These findings suggest that expression of differentiation markers in tumours correlates with less aggressive disease, as would be expected for tumours that retain differentiation capacity, albeit cryptic in the case of ciliated cells. These markers could be used to improve the risk stratification of endometrial cancer patients, thereby improving their management. We further assessed whether consideration of MPST expression could refine the ProMiSE molecular classification system for endometrial tumours. We found that higher expression levels of MPST could be used to refine stratification of three of the four ProMiSE molecular subgroups, and that any level of MPST expression was able to significantly refine risk stratification of the copy number high subgroup which has the worst prognosis. Taken together, this shows that single cell sequencing of putative cells of origin has the potential to uncover novel biomarkers that could be used to guide management of cancers. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Oral contraceptive use is associated with a reduction in the physical size of fallopian tube p53 signatures

Oral contraceptives reduce ovarian cancer risk, but the mechanism of risk reduction is not understood. We examined whether oral contraceptive pill (OCP) use influences p53 signatures, which are putative early fallopian tube precursors for high-grade serous ovarian carcinomas. For this retrospective cohort (n = 250) of subjects aged over 50 years who had fallopian tubes removed at the time of a benign gynecologic procedure, we used health records to identify 72 patients who used OCPs for at least 5 years and 178 subjects with no history of OCP use. Immunohistochemistry for p53 was performed on all fallopian tube sections, with 8 individuals removed for lack of identifiable tissue. p53 Signatures were identified and stratified based on size. Logistic regressions were run to estimate the association between OCP use and p53 lesion and lesion size. There was no difference in the occurrence of p53 lesions with 20 of 70 of OCP users (28.6%) and 57 of 172 of those with no history of OCP use (33.1%). Subjects who used OCPs were more likely to have a small lesion (OR 1.98, 95% CI 1.03 to 3.83) and had decreased risk of having a medium/large lesion (OR 0.38, 95% CI 0.18 to 0.79). A total of 2 serous tubal intraepithelial lesions and 2 serous tubal intraepithelial carcinomas were identified in OCP-naive patients, whereas none were found in those with a history of OCP use. OCP exposure was associated with a shift toward smaller p53 lesion size but was not found to be associated with a difference in the number of p53 lesions between OCP-exposed and unexposed patients. Future research should examine whether OCP use reduces proliferation and clonal expansion of p53 signature lesions toward higher risk precursors and, eventually, cancer. There were no serous tubal intraepithelial lesions and serous tubal intraepithelial carcinomas in patients with OCP exposure.