Association between tubal ligation and endometrial cancer risk: A Swedish population-based cohort study

MYC is Sufficient to Generate Mid-Life High-Grade Serous Ovarian and Uterine Serous Carcinomas in a p53-R270H Mouse Model

Genetically engineered mouse models (GEMM) have fundamentally changed how ovarian cancer etiology, early detection, and treatment are understood. MYC, an oncogene, is amongst the most amplified genes in high-grade serous ovarian cancer (HGSOC), but it has not previously been utilized to drive HGSOC GEMMs. We coupled Myc and dominant-negative mutant p53-R270H with a fallopian tube epithelium (FTE)-specific promoter Ovgp1 to generate a new GEMM of HGSOC. Female mice developed lethal cancer at an average of 14.5 months. Histopathologic examination of mice revealed HGSOC characteristics, including nuclear p53 and nuclear MYC in clusters of cells within the FTE and ovarian surface epithelium. Unexpectedly, nuclear p53 and MYC clustered cell expression was also identified in the uterine luminal epithelium, possibly from intraepithelial metastasis from the FTE. Extracted tumor cells exhibited strong loss of heterozygosity at the p53 locus, leaving the mutant allele. Copy-number alterations in these cancer cells were prevalent, disrupting a large fraction of genes. Transcriptome profiles most closely matched human HGSOC and serous endometrial cancer. Taken together, these results demonstrate that the Myc and Trp53-R270H transgenes were able to recapitulate many phenotypic hallmarks of HGSOC through the utilization of strictly human-mimetic genetic hallmarks of HGSOC. This new mouse model enables further exploration of ovarian cancer pathogenesis, particularly in the 50% of HGSOC which lack homology-directed repair mutations. Histologic and transcriptomic findings are consistent with the hypothesis that uterine serous cancer may originate from the FTE.

SIGNIFICANCE

Mouse models using transgenes which generate spontaneous cancers are essential tools to examine the etiology of human diseases. Here, the first Myc-driven spontaneous model is described as a valid HGSOC model. Surprisingly, aspects of uterine serous carcinoma were also observed in this model.

MYC is sufficient to generate mid-life high-grade serous ovarian and uterine serous carcinomas in a p53-R270H mouse model

Genetically engineered mouse models (GEMM) have fundamentally changed how ovarian cancer etiology, early detection, and treatment is understood. However, previous GEMMs of high-grade serous ovarian cancer (HGSOC) have had to utilize genetics rarely or never found in human HGSOC to yield ovarian cancer within the lifespan of a mouse. MYC, an oncogene, is amongst the most amplified genes in HGSOC, but it has not previously been utilized to drive HGSOC GEMMs. We coupled Myc and dominant negative mutant p53-R270H with a fallopian tube epithelium-specific promoter Ovgp1 to generate a new GEMM of HGSOC. Female mice developed lethal cancer at an average of 15.1 months. Histopathological examination of mice revealed HGSOC characteristics including nuclear p53 and nuclear MYC in clusters of cells within the fallopian tube epithelium and ovarian surface epithelium. Unexpectedly, nuclear p53 and MYC clustered cell expression was also identified in the uterine luminal epithelium, possibly from intraepithelial metastasis from the fallopian tube epithelium (FTE). Extracted tumor cells exhibited strong loss of heterozygosity at the p53 locus, leaving the mutant allele. Copy number alterations in these cancer cells were prevalent, disrupting a large fraction of genes. Transcriptome profiles most closely matched human HGSOC and serous endometrial cancer. Taken together, these results demonstrate the Myc and Trp53-R270H transgene was able to recapitulate many phenotypic hallmarks of HGSOC through the utilization of strictly human-mimetic genetic hallmarks of HGSOC. This new mouse model enables further exploration of ovarian cancer pathogenesis, particularly in the 50% of HGSOC which lack homology directed repair mutations. Histological and transcriptomic findings are consistent with the hypothesis that uterine serous cancer may originate from the fallopian tube epithelium.

Epidemiological trends and risk factors of gynecological cancers: an update

Gynecological cancers, the most common cancer among women worldwide, disrupt the function of women's reproductive system, significantly impacting the quality of life. The epidemiological patterns of gynecological cancers differ in various regions and alter over time. The main challenge to deal with women's cancers is focusing on potential plans to improve patient outcomes. The epidemiology and general risk elements of gynecological cancers are important in the management of these cancers, so all of the reported risk factors in gynecological cancers have been evaluated in the present review. Due to the role of gynecological cancers in women's health, preventive measures and modifiable lifestyles together with early detection in high-risk groups are effective strategies that can reduce mortality rates. This review summarizes the epidemiology and global risk factors of gynecological cancers alongside others to better management of these malignancies and improve the quality of life in the affected patients.

Executive Summary of the Uterine Cancer Evidence Review Conference

Evidence for uterine cancer prevention, diagnosis, and special issues from the Uterine Cancer Evidence Review Conference is summarized.

The Centers for Disease Control and Prevention recognized the need for educational materials for clinicians on the prevention and early diagnosis of gynecologic cancers. The American College of Obstetricians and Gynecologists convened a panel of experts in evidence review from the Society for Academic Specialists in General Obstetrics and Gynecology and content experts from the Society of Gynecologic Oncology to review relevant literature, best practices, and existing practice guidelines as a first step toward developing evidence-based educational materials for women's health care clinicians about uterine cancer. Panel members conducted structured literature reviews, which were then reviewed by other panel members and discussed at a virtual meeting of stakeholder professional and patient advocacy organizations in January 2021. This article is the evidence summary of the relevant literature and existing recommendations to guide clinicians in the prevention, early diagnosis, and special considerations of uterine cancer. Substantive knowledge gaps are noted and summarized to provide guidance for future research.

Fallopian tube abnormalities in uterine serous carcinoma

OBJECTIVE

Uterine serous carcinoma (USC) is presumed to arise from endometrial intra-epithelial carcinoma (EIC), whereas tubo-ovarian high-grade serous carcinomas have similar precursor lesions in the Fallopian tube, i.e. serous tubal intra-epithelial carcinoma (STIC). The presence of Fallopian tube abnormalities and their clonal relationship to the concurrent USC was investigated.

METHODS

In this multicenter study, all patients treated for USC between 1992 and 2017 were retrospectively identified. Histopathological diagnosis of USC, EIC and STIC was revised by an expert pathologist. Additionally, all Fallopian tube sections were immunohistochemically stained (p53 and Ki-67). Fallopian tube abnormalities were classified as either p53 signature, serous tubal intra-epithelial lesion (STIL) or STIC. The USCs and Fallopian tube abnormalities were analyzed by targeted next-generation sequencing.

RESULTS

In 168 included patients, Fallopian tube abnormalities were found in 27.4% (46/168): p53-signatures in 17.9% (30/168), STILs in 3.0% (5/168) and STICs in 6.5% (11/168). In subgroup analysis, STICs were found in 9.5% (11/115) of patients with at least one section of the fimbriated end embedded. Next-generation sequencing showed identical TP53-mutations in the STIC and corresponding USC.

CONCLUSIONS

In conclusion, the presence of Fallopian tube abnormalities was shown in a high percentage of patients with USC, representing either true precursor lesions or metastasized disease.

Tubal ligation and endometrial Cancer risk: a global systematic review and meta-analysis

BACKGROUND

Studies on relationship between tubal ligation and endometrial cancer have led to contradictory findings. In several studies, however, a reduced endometrial cancer risk was suggested following tubal ligation. Therefore, a systematic review and meta-analysis was conducted to examine the relationship between tubal ligation and endometrial cancer risk.

METHODS

In this systematic review and meta-analysis, PubMed/Medline, Web of Science, Scopus, Embase, and Google Scholar were searched for relevant studies published up to May 30th, 2018. We compared endometrial cancer risk in women with and without tubal ligation in retrieved studies.

RESULTS

Two hundred nine studies were initially retrieved from the data bases. After exclusion of duplicates and studies which did not meet inclusion criteria, ten cohort and case-control studies, including 6,773,066 cases, were entered into the quantitative meta-analysis. There was 0.90% agreement between two researchers who searched and retrieved the studies. The summary OR (SOR) was reported using a random effect model. Begg's test suggested that there was no publication bias, but a considerable heterogeneity was observed (I² = 95.4%, P = 0.001). We pooled the raw number of tables cells (i.e. a, b, c, and d) of eight studies. The SOR suggested that tubal ligation was significantly associated with a lower risk of endometrial cancer (SOR = 0.577, 95% CI = 0.420-0.792). Also, given the rare nature of endometrial cancer (< 5%), different effect sizes were considered as comparable measures of risk. Therefore we pooled ten studies and SOR of these studies revealed that tubal ligation was significantly associated with a lower risk of endometrial cancer (SOR = 0.696, 95% CI = 0.425-0.966). Besides that, we pooled eight studies in which adjusted effect sizes were reported and a subsequent analysis revealed that the summary estimate of adjusted odds ratio (SAOR) was significant (SAOR = 0.862, 95% CI = 0.698-1.026).

CONCLUSIONS

This study revealed a protective effect of tubal ligation on endometrial cancer risk (approximately 42% lower risk of cancer). It is recommended that studies should be designed to reveal mechanisms of this relationship.

Opportunistic prophylactic salpingectomy for prevention of ovarian cancer: What do national societies advise?

OBJECTIVE

To determine how many FIGO (International Federation of Obstetrics and Gynecology) member societies have statements regarding opportunistic (incidental, prophylactic, risk-reducing) salpingectomy at the time of benign gynecologic surgery and to categorize statements as positive, negative or ambivalent.

STUDY DESIGN

The websites of the 130 FIGO member societies were searched for statements on opportunistic salpingectomy. We looked for separate statements and statements embedded in other documents such as clinical guidelines as well as statements by national societies of gynecologic oncology. If nothing was found on the websites we contacted societies by Email or fax.

RESULTS

As of early 2018, 13 FIGO member societies representing 14 countries have statements regarding opportunistic salpingectomy. Nine were separate, stand-alone statements, four were embedded in other documents. Nine of the 13 statements (from Canada, Finland, U.S.A., Great Britain, Australia and New Zealand, Denmark, Austria, Turkey, and Japan) support consideration of opportunistic salpingectomy in appropriate women and four (from Germany, Sweden, Norway, and France) are ambivalent; there are no statements recommending against opportunistic salpingectomy.

CONCLUSION

In 2018 only a small minority of FIGO members have statements on opportunistic prophylactic salpingectomy. These statements are ambivalent or supportive, none is negative.