Survival of patients with ovarian cancer due to a mismatch repair defect

Updates in gynecologic care for individuals with lynch syndrome

Lynch syndrome is an autosomal dominant hereditary cancer syndrome caused by germline pathogenic variants (PVs) in DNA mismatch repair genes (MLH1, MSH2, PMS2, MSH6) or the EPCAM gene. It is estimated to affect 1 in 300 individuals and confers a lifetime risk of cancer of 10-90%, depending on the specific variant and type of cancer. Lynch syndrome is the most common cause of inherited colorectal cancer, but for women, endometrial cancer is more likely to be the sentinel cancer. There is also evidence that certain PVs causing Lynch syndrome confer an increased risk of ovarian cancer, while the risk of ovarian cancer in others is not well defined. Given this, it is essential for the practicing gynecologist and gynecologic oncologist to remain up to date on the latest techniques in identification and diagnosis of individuals with Lynch syndrome as well as evidence-based screening and risk reduction recommendations for those impacted. Furthermore, as the landscape of gynecologic cancer treatment shifts towards treatment based on molecular classification of tumors, knowledge of targeted therapies well-suited for mismatch repair deficient Lynch tumors will be crucial. The objective of this review is to highlight recent updates in the literature regarding identification and management of individuals with Lynch syndrome as it pertains to endometrial and ovarian cancers to allow gynecologic providers the opportunity to both prevent and identify Lynch-associated cancers earlier, thereby reducing the morbidity and mortality of the syndrome.

Frequency and clinical features of deficient mismatch repair in ovarian clear cell and endometrioid carcinoma

Objective

To clarify the frequency of deficient mismatch repair (dMMR) in Japanese ovarian cancer patients, we examined microsatellite instability (MSI) status and immunohistochemistry (IHC) subtypes, including endometrioid carcinoma (EMC), clear cell carcinoma (CCC), or a mixture of both (Mix).

Methods

We registered 390 patients who were diagnosed with EMC/CCC/Mix between 2006 and 2015 and treated at seven participating facilities. For 339 patients confirmed eligible by the Central Pathological Review Board, MSI, IHC, and MutL homolog 1 methylation analyses were conducted. The tissues of patients with Lynch syndrome (LS)-related cancer histories, such as colorectal and endometrial cancer, were also investigated.

Results

MSI-high (MSI-H) status was observed in 2/217 CCC (0.9%), 10/115 EMC (8.7%), and 1/4 Mix (25%). Additionally, loss of MMR protein expression (LoE-MMR) was observed in 5/219 (2.3%), 16/115 (14.0%), and 1/4 (25%) patients with CCC, EMC, and Mix, respectively. Both MSI-H and LoE-MMR were found significantly more often in EMC (p<0.001). The median (range) ages of patients with MMR expression and LoE-MMR were 54 (30–90) and 46 (22–76) (p=0.002), respectively. In the multivariate analysis, advanced stage and histological type were identified as prognostic factors.

Conclusion

The dMMR rate for EMC/CCC was similar to that reported in Western countries. In Japan, it is assumed that the dMMR frequency is higher because of the increased proportion of CCC.

The deficient mismatch repair (dMMR) rate in Japanese patients is currently unknown. This study determined the frequency of dMMR in Japanese ovarian cancer patients. The dMMR rate was similar to that reported in Western countries. We identified potential criteria for implementing microsatellite instability and immunohistochemistry analyses in Lynch syndrome screening.

Biomarkers in Gynecologic Tumors

Gynecologic malignancies are one of the most frequent cancers amongst women. Biomarkers are crucial for the differential diagnosis of adnexal masses; however, their potential for diagnosis is limited. In the era of difficulty in ovarian cancer screening, novel biomarkers are defined, but CA125 still remains the most valuable one. Circulating tumor DNAs, DNA hypermethylation, metabolites, microRNAs, and kallikreins have recently turned out as ovarian cancer biomarkers and are being applied to clinical practice. For uterine cancer, genomic classification has now been described, it will be used as a prognostic tool. In this chapter, we describe ovarian, endometrial, and cervical cancer biomarkers in detail.

Epithelial Ovarian Cancer: Providing Evidence of Predisposition Genes

Epithelial ovarian cancer (EOC) is one of the cancers most influenced by hereditary factors. A fourth to a fifth of unselected EOC patients carry pathogenic variants (PVs) in a number of genes, the majority of which encode for proteins involved in DNA mismatch repair (MMR) pathways. PVs in BRCA1 and BRCA2 genes are responsible for a substantial fraction of hereditary EOC. In addition, PV genes involved in the MMR pathway account for 10–15% of hereditary EOC. The identification of women with homologous recombination (HR)-deficient EOCs has significant clinical implications, concerning chemotherapy regimen planning and development as well as the use of targeted therapies such as poly(ADP-ribose) polymerase (PARP) inhibitors. With several genes involved, the complexity of genetic testing increases. In this context, next-generation sequencing (NGS) allows testing for multiple genes simultaneously with a rapid turnaround time. In this review, we discuss the EOC risk assessment in the era of NGS.

Gynecological Cancers in Lynch Syndrome: A Comparison of the Histological Features with Sporadic Cases of the General Population

Introduction: About 5% of endometrial cancers (ECs) are attributed to an inherited predisposition, for which Lynch syndrome (LS) accounts for the majority of cases. Women with LS have a 40−60% predicted lifetime risk of developing EC, in addition to a 40−80% lifetime risk of developing colorectal cancer and other cancers. In this population, the lifetime risk of developing ovarian cancer (OC) is 10−12%. Object: to compare the histopathological features of LS-associated EC and OC with sporadic cancers in order to evaluate whether there are differences in terms of age at diagnosis, site of occurrence in the uterus, histological type, stage at diagnosis, and tumor grading. Materials and methods: we compared data obtained from 96 patients with LS-associated gynecological cancers (82 with EC and 14 with OC) to a control group (CG) of 209 patients who developed sporadic EC, and a CG of 187 patients with sporadic OC. Results: The mean age at diagnosis of LS-associated EC and OC was much lower than in the control groups. In both groups with EC, the endometrioid histotype was the most frequently occurring histotype. However, among LS women there was a significantly higher incidence of clear cell tumors (11% versus 2.4% in the CG, p = 0.0001). Similar to the sporadic cancer cases, most of the LS-associated ECs presented at an early stage (89% of cases at FIGO I-II stage). In the LS group, the tumor frequently involved only the inner half of the endometrium (77% of cases, p < 0.01). In the LS group, 7.3% of ECs were localized to the lower uterine segment (LUS), whereas no cancer developed in the LUS in the CG. No serous OCs were diagnosed in the LS group (versus 45.5% in the CG, p = 0.0009). Most of the LS-associated OCs presented at an early stage (85% of cases at FIGO I-II stages, p < 0.01). Conclusion: LS-associated EC and OC seem to have peculiar features, occurring at a younger age and at an earlier stage. In LS, EC less frequently involves the outer half of the endometrium, with a more frequent occurrence in the LUS. The presence of clear cell EC was more frequently observed, whereas in OC, the predominant histotype was endometrioid.

Cost-effectiveness of prophylactic hysterectomy in first-degree female relatives with Lynch syndrome of patients diagnosed with colorectal cancer in the United States: a microsimulation study

Background

To evaluate the cost‐effectiveness of prophylactic hysterectomy (PH) in women with Lynch syndrome (LS).

Methods

We developed a microsimulation model incorporating the natural history for the development of hyperplasia with and without atypia into endometrial cancer (EC) based on the MISCAN‐framework. We simulated women identified as first‐degree relatives (FDR) with LS of colorectal cancer patients after universal testing for LS. We estimated costs and benefits of offering this cohort PH, accounting for reduced quality of life after PH and for having EC. Three minimum ages (30/35/40) and three maximum ages (70/75/80) were compared to no PH.

Results

In the absence of PH, the estimated number of EC cases was 300 per 1,000 women with LS. Total associated costs for treatment of EC were $5.9 million. Offering PH to FDRs aged 40–80 years was considered optimal. This strategy reduced the number of endometrial cancer cases to 5.4 (−98%), resulting in 516 quality‐adjusted life years (QALY) gained and increasing the costs (treatment of endometrial cancer and PH) to $15.0 million (+154%) per 1,000 women. PH from earlier ages was more costly and resulted in fewer QALYs, although this finding was sensitive to disutility for PH.

Conclusions

Offering PH to 40‐ to 80‐year‐old women with LS is expected to add 0.5 QALY per person at acceptable costs. Women may decide to have PH at a younger age, depending on their individual disutility for PH and premature menopause.

Historical review of Lynch syndrome

Lynch syndrome was formerly known as Hereditary Nonpolyposis Colorectal Cancer. Currently, these two nomenclatures each have their unique definitions and are no longer used interchangeably. The history of hereditary nonpolyposis colorectal cancer was first recognized formally in the literature by Henry Lynch in 1967. With advances of molecular genetics, there has been a transformation from clinical phenotype to genotype diagnostics. This has led to the ability to diagnose affected patients before they manifest with cancer, and therefore allow preventative surveillance strategies. Genotype diagnostics has shown a difference in penetrance of different cancer risks dependent on the gene containing the mutation. Surgery is recommended as prevention for some cancers; for others they are reserved for once cancer is noted. Various surveillance strategies are recommended dependent on the relative risk of cancer and the ability to intervene with surgery to impact on survival. Risk reduction through aspirin has shown some recent promise, and continues to be studied.

The Potential Role of iNOS in Ovarian Cancer Progression and Chemoresistance

Inducible nitric oxide synthase (iNOS), the enzyme responsible for nitric oxide (NO) production, is not present in most cells under normal conditions. The expression of its mRNA, as well as its protein synthesis and full enzymatic activity, undergoes multilevel regulation including transcriptional and posttranscriptional mechanisms, the availability of iNOS substrate and cofactors and oxygen tension. However, in various malignant diseases, such as ovarian cancer, the intracellular mechanisms controlling iNOS are dysregulated, resulting in the permanent induction of iNOS expression and activation. The present review summarizes the multistaged processes occurring in normal cells that promote NO synthesis and focuses on factors regulating iNOS expression in ovarian cancer. The possible involvement of iNOS in the chemoresistance of ovarian cancer and its potential as a prognostic/predictive factor in the course of disease development are also reviewed. According to the available yet limited data, it is difficult to draw unequivocal conclusions on the pros and cons of iNOS in ovarian cancer. Most clinical data support the hypothesis that high levels of iNOS expression in ovarian tumors are associated with a greater risk of disease relapse and patient death. However, in vitro studies with various ovarian cancer cell lines indicate a correlation between a high level of iNOS expression and sensitivity to cisplatin.

Women's preferences for cancer risk management strategies in Lynch syndrome

OBJECTIVE

We assessed preferences for cancer risk management strategies for Lynch syndrome (LS) in LS-affected women.

METHODS

Women with LS aged ≥25 years evaluated 9 cancer risk management strategies using a visual analog scale (VAS) and modified standard gamble (SG). For the VAS, women ranked each strategy ranging from 0 (least preferred) to 100 (most preferred). VAS scores were calculated by dividing the corresponding number by 100. Scores closer to 1.0 reflected more favorable strategies. For the SG, participants were asked to specify their expected threshold of lifetime risk of endometrial or colorectal cancer, ranging from 0 to 100%, at which they would consider undertaking each strategy. Strategies included chemoprevention, cancer screening, and preventive surgery. Cancer worry and perceived cancer risk measures were collected on a subset of participants.

RESULTS

Sixty-one women completed preference assessments. By VAS, annual combined screening was the most preferred, followed by annual screenings and chemoprevention with oral contraceptives. By SG, women were the most willing to endorse oral contraceptives and biannual screening strategies at the lowest threshold of lifetime risk followed by annual screening strategies. Surgical interventions were the least preferred strategies using both VAS and SG. Women with a family history of gynecologic or colorectal cancer were less likely to consider prevention or screening options compared to women without a family history. Cancer worry was higher among women with a positive family history of LS cancer.

CONCLUSION

Understanding women's preferences may facilitate optimal use and adherence to cancer risk management strategies.

Microsatellite Instability Is Associated With the Presence of Lynch Syndrome Pan-Cancer

PURPOSE

Microsatellite instability (MSI) and/or mismatch repair deficiency (MMR-D) testing has traditionally been performed in patients with colorectal (CRC) and endometrial cancer (EC) to screen for Lynch syndrome (LS)-associated cancer predisposition. The recent success of immunotherapy in high-frequency MSI (MSI-H) and/or MMR-D tumors now supports testing for MSI in all advanced solid tumors. The extent to which LS accounts for MSI-H across heterogeneous tumor types is unknown. Here, we establish the prevalence of LS across solid tumors according to MSI status.

METHODS

MSI status was determined using targeted next-generation sequencing, with tumors classified as MSI-H, MSI-indeterminate, or microsatellite-stable. Matched germline DNA was analyzed for mutations in LS-associated mismatch repair genes ( MLH1, MSH2, MSH6, PMS2, EPCAM). In patients with LS with MSI-H/I tumors, immunohistochemical staining for MMR-D was assessed.

RESULTS

Among 15,045 unique patients (more than 50 cancer types), LS was identified in 16.3% (53 of 326), 1.9% (13 of 699), and 0.3% (37 of 14,020) of patients with MSI-H, MSI-indeterminate, and microsatellite-stable tumors, respectively ( P < .001). Among patients with LS with MSI-H/I tumors, 50% (33 of 66) had tumors other than CRC/EC, including urothelial, prostate, pancreas, adrenocortical, small bowel, sarcoma, mesothelioma, melanoma, gastric, and germ cell tumors. In these patients with non-CRC/EC tumors, 45% (15 of 33) did not meet LS genetic testing criteria on the basis of personal/family history. Immunohistochemical staining of LS-positive MSI-H/I tumors demonstrated MMR-D in 98.2% (56 of 57) of available cases.

CONCLUSION

MSI-H/MMR-D is predictive of LS across a much broader tumor spectrum than currently appreciated. Given implications for cancer surveillance and prevention measures in affected families, these data support germline genetic assessment for LS for patients with an MSI-H/MMR-D tumor, regardless of cancer type or family cancer history.

Adjuvant chemotherapy in patients with stage I endometrioid or clear cell ovarian cancer in the platinum era: a Surveillance, Epidemiology, and End Results Cohort Study, 2000-2013

Background

We sought to evaluate the impact of adjuvant chemotherapy on overall survival (OS) in patients with stage I endometrioid epithelial ovarian cancer (EEOC) or ovarian clear cell cancer (OCCC) using a national database.

Patients and methods

The Surveillance, Epidemiology, and End Results database was used to identify patients diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage I EEOC or OCCC from 2000 to 2013. We sought to identify predictors of chemotherapy use and to assess the impact of chemotherapy on OS in these patients. OS was compared using the log-rank test and the Cox proportional hazards model.

Results

In all, 3552 patients with FIGO stage I EEOC and 1995 patients with stage I OCCC were identified. Of the 1600 patients (45%) with EEOC who underwent adjuvant chemotherapy, the 5-year OS rate was 90%, compared with 89% for those who did not undergo adjuvant chemotherapy (P = 0.807). Of the 1374 (69%) patients with OCCC who underwent adjuvant chemotherapy, the 5-year OS rate was 85%, compared with 83% (P = 0.439) for those who did not undergo adjuvant chemotherapy. Chemotherapy use was associated with younger age, higher substage, and more recent year of diagnosis for both the EEOC and OCCC groups. Only in the subgroup of patients with FIGO substage IC, grade 3 EEOC (n = 282) was chemotherapy associated with an improved 5-year OS-81% compared with 62% (P = 0.003) in untreated patients (HR: 0.583; 95% CI: 0.359-0.949; P = 0.030). In patients with OCCC, there was no significant effect of adjuvant chemotherapy on OS in any substage.

Conclusions

Adjuvant chemotherapy was associated with improved OS only in patients with substage IC, grade 3 EEOC. In stage I OCCC, adjuvant chemotherapy was not associated with improved OS.

Role of tumor microenvironment in ovarian cancer pathobiology

Ovarian cancer is the fifth most common cancer affecting the female population and at present, stands as the most lethal gynecologic malignancy. Poor prognosis and low five-year survival rate are attributed to nonspecific symptoms and below par diagnostic criteria at early phases along with a lack of effective treatment at advanced stages. It is thus of utmost importance to understand ovarian carcinoma through several lenses including its molecular pathogenesis, epidemiology, histological subtypes, hereditary factors, diagnostic approaches and methods of treatment. Above all, it is crucial to dissect the role that the unique peritoneal tumor microenvironment plays in ovarian cancer progression and metastasis. This review seeks to highlight several important aspects of ovarian cancer pathobiology as a means to provide the necessary background to approach ovarian malignancies in the future.

Distinct gene expression profiles in ovarian cancer linked to Lynch syndrome

Ovarian cancer linked to Lynch syndrome represents a rare subset that typically presents at young age as early-stage tumors with an overrepresentation of endometrioid and clear cell histologies. We investigated the molecular profiles of Lynch syndrome-associated and sporadic ovarian cancer with the aim to identify key discriminators and central tumorigenic mechanisms in hereditary ovarian cancer. Global gene expression profiling using whole-genome c-DNA-mediated Annealing, Selection, extension, and Ligation was applied to 48 histopathologically matched Lynch syndrome-associated and sporadic ovarian cancers. Lynch syndrome-associated and sporadic ovarian cancers differed by 349 significantly deregulated genes, including PTPRH, BIRC3, SHH and TNFRSF6B. The genes involved were predominantly linked to cell growth, proliferation, and cell-to-cell signaling and interaction. When stratified for histologic subtype, hierarchical clustering confirmed distinct differences related to heredity in the endometrioid and serous subtypes. Furthermore, separate clustering was achieved in an independent, publically available data set. The distinct genetic signatures in Lynch syndrome-associated and sporadic ovarian cancers point to alternative preferred tumorigenic routes and suggest that genetic discriminators may be relevant for molecular diagnostics and targeted therapeutics.

Management of ovarian and endometrial cancers in women belonging to HNPCC carrier families: review of the literature and results of cancer risk assessment in Polish HNPCC families

BACKGROUND

Over half the cancer deaths in HNPCC families are due to extra-colonic malignancies that include endometrial and ovarian cancers. The benefits of surveillance for gynecological cancers are not yet proven and there is no consensus on the optimal surveillance recommendations for women with MMR mutations.

METHODS

We performed a systematic review of the literature and evaluated gynecological cancer risk in a series of 631 Polish HNPCC families classified into either Lynch Syndrome (LS, MMR mutations detected) or HNPCC (fulfillment of the Amsterdam or modified Amsterdam criteria).

RESULTS

Published data clearly indicates no benefit for ovarian cancer screening in contrast to risk reducing surgery. We confirmed a significantly increased risk of OC in Polish LS families (OR = 4,6, p < 0.001) and an especially high risk of OC was found for women under 50 years of age: OR = 32,6, p < 0.0001 (95% CI 12,96-81,87). The cumulative OC risk to 50 year of life was calculated to be 10%. Six out of 19 (32%) early-onset patients from LS families died from OC within 2 years of diagnosis. We confirmed a significantly increased risk of EC (OR = 26, 95% CI 11,36-58,8; p < 0,001). The cumulative risk for EC in Polish LS families was calculated to be 67%.

CONCLUSIONS

Due to the increased risk of OC and absence of any benefit from gynecological screening reported in the literature it is recommended that prophylactic oophorectomy for female carriers of MMR mutations after 35 year of age should be considered as a risk reducing option. Annual transvaginal ultrasound supported by CA125 or HE4 marker testing should be performed after prophylactic surgery in these women. Due to the high risk of EC it is reasonable to offer, after the age of 35 years, annual clinical gynecologic examinations with transvaginal ultrasound supported by routine aspiration sampling of the endometrium for women from either LS or HNPCC families. An alternative option, which could be taken into consideration for women preferring surgical prevention, is risk reducing total hysterectomy (with bilateral salpingo-oophorectomy) for carriers after childbearing is complete.

Hereditary cancer syndromes with high risk of endometrial and ovarian cancer: surgical options for personalized care

Cancer genomics has increased our recognition of specific hereditary cancer mutations. Hereditary breast and ovarian cancer (HBOC) syndrome and Lynch syndrome are two such entities in which women carrying specific mutations may be at high risk for developing breast, ovarian, and/or endometrial cancers. Risk reducing surgery such as prophylactic mastectomy, oophorectomy, and/or hysterectomy may allow women to decrease these risks after completing childbearing. Background, indications, and consequences of these procedures are reviewed.

Features of ovarian cancer in Lynch syndrome (Review)

Lynch syndrome is a hereditary ovarian cancer with a prevalence of 0.9-2.7%. Lynch syndrome accounts for 10-15% of hereditary ovarian cancers, while hereditary breast and ovarian cancer syndrome accounts for 65-75% of these cancers. The lifetime risk for ovarian cancer in families with Lynch syndrome is ~8%, which is lower than colorectal and endometrial cancers, and ovarian cancer is not listed in the Amsterdam Criteria II. More than half of sporadic ovarian cancers are diagnosed in stage III or IV, but ≥80% of ovarian cancers in Lynch syndrome are diagnosed in stage I or II. Ovarian cancers in Lynch syndrome mostly have non-serous histology and different properties from those of sporadic ovarian cancers. A screening method for ovarian cancers in Lynch syndrome has yet to be established and clinical studies of prophylactic administration of oral contraceptives are not available. However, molecular profiles at the genetic level indicate that ovarian cancer in Lynch syndrome has a more favorable prognosis than sporadic ovarian cancer. Inhibitors of the phosphatidylinositol 3-kinase/mammalian target of the rapamycin pathway and anti-epidermal growth factor antibodies may have efficacy for the disease. To the best of our knowledge, this is the first review focusing on ovarian cancer in Lynch syndrome.

Review of findings in prophylactic gynaecological specimens in Lynch syndrome with literature review and recommendations for grossing

AIMS

Prophylactic hysterectomy with bilateral salpingo-oophorectomy is being increasingly undertaken in patients with Lynch syndrome (LS). The pathological features in such specimens are not well described and, unlike the SEE-FIM protocol for salpingo-oophorectomy specimens in BRCA1/2 mutation carriers and the gastrectomy grossing protocols for patients with CDH1 (E-cadherin) mutations, guidelines have not been devised for the grossing of prophylactic gynaecological specimens from LS patients. We aimed to review the pathological findings in a series of prophylactic gynaecological specimens from LS patients and develop guidelines for the grossing of these specimens.

METHODS AND RESULTS

We reviewed the pathological findings in 25 prophylactic gynaecological specimens from LS patients and audited the grossing protocols in different centres across Ontario, Canada. We found a 32% incidence of endometrial carcinoma or a precursor lesion; the two endometrial cancers identified were low-grade, low-stage endometrioid adenocarcinomas. To address the absence of guidelines for pathological examination, we undertook a literature review of gynaecological malignancies and incidental findings in prophylactic specimens in LS patients.

CONCLUSION

We provide recommendations regarding the grossing of such specimens which includes in-toto examination of the lower uterine segment, endometrium, ovaries and fallopian tubes with representative sampling of the cervix.

Excess of extracolonic non-endometrial multiple primary cancers in MSH2 germline mutation carriers over MLH1

BACKGROUND

The lynch syndrome (LS) tumor spectrum involves colorectal cancer (CRC), endometrial cancer (EC), and less frequently various extracolonic non-endometrial cancers (non-EC). The organ-specific survival rates of these patients are well defined, however, the collective survival of all-cancers combined (CRC + EC + non-EC) are unclear.

METHODS

Fifty-two MSH2 patients and 68 MLH1 patients were followed for a median of 6.3 years after diagnosis of first cancer, regardless of type. The proportions of CRC only, EC, non-EC, and multiple primary cancers were compared between the two genotypes. Kaplan-Meier curves were developed for survival comparisons.

RESULTS

MSH2 patients present less frequently with only CRC (37% MSH2, 62% MLH1, P = 0.0096), manifest more multiple primary cancers (38% MSH2, 18% MLH1, P = 0.013), develop more extracolonic cancers (62% MSH2, 38% MLH1, P = 0.003), non-EC only cancers (46% MSH2, 24% MLH1, P = 0.028) and carry a greater risk for urinary tract cancer (UTC) (13.4% MSH2, 1.5% MLH1, P = 0.024). There was no difference in 10-year survival between the two groups (P = 0.4).

CONCLUSION

The additional propensity for UTC in MSH2 carriers argues in favor of UTC screening in MSH2 individuals. Other types of cancer screening should be tailored to the expression history of the specific LS mutation.

Hereditary breast and ovarian cancer susceptibility genes (review)

Women with hereditary breast and ovarian cancer (HBOC) syndrome represent a unique group who are diagnosed at a younger age and result in an increased lifetime risk for developing breast, ovarian and other cancers. This review integrates recent progress and insights into the molecular basis that underlie the HBOC syndrome. A review of English language literature was performed by searching MEDLINE published between January 1994 and October 2012. Mutations and common sequence variants in the BRCA1 and BRCA2 (BRCA) genes are responsible for the majority of HBOC syndrome. Lifetime cancer risks in BRCA mutation carriers are 60-80% for breast cancer and 20-40% for ovarian cancer. Mutations in BRCA genes cannot account for all cases of HBOC, indicating that the remaining cases can be attributed to the involvement of constitutive epimutations or other cancer susceptibility genes, which include Fanconi anemia (FA) cluster (FANCD2, FANCA and FANCC), mismatch repair (MMR) cluster (MLH1, MSH2, PMS1, PMS2 and MSH6), DNA repair cluster (ATM, ATR and CHK1/2), and tumor suppressor cluster (TP53, SKT11 and PTEN). Sporadic breast cancers with TP53 mutations or epigenetic silencing (hypermethylation), ER- and PgR-negative status, an earlier age of onset and high tumor grade resemble phenotypically BRCA1 mutated cancers termed 'BRCAness', those with no BRCA mutations but with a dysfunction of the DNA repair system. In conclusion, genetic or epigenetic loss-of-function mutations of genes that are known to be involved in the repair of DNA damage may lead to increased risk of developing a broad spectrum of breast and ovarian cancers.

Endometrial and ovarian cancer in lynch syndrome

Lynch syndrome (LS) is an autosomal dominant familial cancer risk syndrome that occurs due to a germline mutation in one of several mismatch repair genes and is associated with an increased risk of colorectal, endometrial, and ovarian cancer. The risk of endometrial cancer equals or exceeds that of colorectal cancer in women with LS. The diagnosis of gynecologic cancer precedes that of colorectal cancer in over half of women with metachronous gynecologic and colon cancers, making gynecologic cancer a "sentinel cancer" for LS. There are no studies addressing the effectiveness or safety of chemoprevention for women with LS. Surveillance with gynecologic examination including assessment of symptoms, transvaginal pelvic ultrasonography, endometrial biopsy, and CA125 tumor marker assessment can be offered, but has not been shown to improve outcomes for these patients. Prophylactic hysterectomy with bilateral salpingo-oophorectomy performed after the completion of childbearing may be offered for gynecologic cancer prevention.

Frequency of mutations in mismatch repair genes in a population-based study of women with ovarian cancer

Background:

Mutations in genes for hereditary non-polyposis colorectal cancer (HNPCC) in ovarian cancer patients remains poorly defined. We sought to estimate the frequency and characteristics of HNPCC gene mutations in a population-based sample of women with epithelial ovarian cancer.

Methods:

The analysis included 1893 women with epithelial ovarian cancer ascertained from three population-based studies. Full-germline DNA sequencing of the coding regions was performed on three HNPCC genes, MLH1, MSH2 and MSH6. Collection of demographic, clinical and family history information was attempted in all women.

Results:

Nine clearly pathogenic mutations were identified, including five in MSH6, two each in MLH1 and MSH2. In addition, 28 unique predicted pathogenic missense variants were identified in 55 patients. Pathogenic mutation carriers had an earlier mean age at diagnosis of ovarian cancer, overrepresentation of cancers with non-serous histologies and a higher number of relatives with HNPCC-related cancers.

Conclusions:

Our findings suggest that fewer than 1% of women with ovarian cancer harbour a germline mutation in the HNPCC genes, with overrepresentation of MSH6 mutations. This represents a lower-range estimate due to the large number of predicted pathogenic variants in which pathogenicity could not definitively be determined. Identification of mismatch repair gene mutations has the potential to impact screening and treatment decisions in these women.

Impact of gynecological screening in Lynch syndrome carriers with an MSH2 mutation

Lifetime risk of developing endometrial cancer in Lynch syndrome carriers is very high and females are also at an increased risk of developing ovarian cancer. The aim of the study was to determine the impact of gynecological screening in MSH2 mutation carriers. Gynecological cancer incidence and overall survival was compared in female mutation carriers who received gynecological screening (cases) and in matched controls. Controls were randomly selected from non-screened mutation carriers who were alive and disease-free at the age the case entered the screening program. Median age to diagnosis of gynecological cancer was 54 years in the screened group compared to 56 years in controls (p = 0.50). Stage I or II cancer was diagnosed in 92% of screened patients compared to 71% in the control group (p = 0.17). Two of three deaths in the screened group were the result of ovarian cancer. Mean survival in the screened group was 79 years compared to 69 years in the control group (p = 0.11), likely associated with concomitant colonoscopy screening. Gynecological screening did not result in earlier gynecologic cancer detection and despite screening two young women died from ovarian cancer suggesting that prophylactic hysterectomy with bilateral salpingo-oophorectomy be considered in female mutation carriers who have completed childbearing.

Evaluation of microsatellite instability in women with epithelial ovarian cancer

The function of microsatellite instability (MSI) and the optimal panel of markers for epithelial ovarian cancer (EOC) are not well established. This study aimed to use the National Cancer Institute (NCI) markers BAT25, BAT26, D2S123, D5S346 and D17S250 to evaluate MSI in patients with ovarian serous cystadenocarcinoma, compared with ovarian serous cystadenoma and normal ovaries. A total of 37 patients were divided into three groups, as follows: cystadenocarcinoma (n=13), cystadenoma (n=10) and normal ovaries (n=14). DNA was extracted with TRIzol and quantified by spectrophotometry. MSI was evaluated by polymerase chain reaction (PCR), and classified as high (MSI-H), low (MSI-L) or stable (MSS). FIGO staging was I/II in 23.1% and III/IV in 76.9% of the cystadenocarcinoma group. Polymorphisms were found using at least one marker in 32 women, and were observed with D2S123 (83.7%), D17S250 (81.1%), D5S346 (72.9%), BAT25 (21.6%) and BAT26 (16.2%) markers. In the cystadenocarcinoma group, BAT25, BAT26, D2S123, D5S346 and D17S250 markers were positive in 30.8, 76.9, 53.8, 69.2 and 69.2% of patients, respectively. The same markers were positive in 30, 50, 40, 60 and 30% of the cystadenoma group, and 50, 71.4, 71.4, 64.3 and 63.3% in the normal ovary group, respectively. MSI-H was present in 84.6, 60 and 78.6% of the cystadenocarcinoma, cystadenoma and normal patients, respectively. MSI-L was detected in 0, 30 and 7.1%, and MSS was identified in 15.4, 10 and 14.3% of the cystadenocarcinoma, cystadenoma and normal patients, respectively. The frequency of MSI in both benign epithelial ovarian neoplasms and in normal ovaries was high, as well as in EOC, with no statistically significant difference between the groups. This suggests that MSI may arise as a consequence of the ovulatory process, and not solely as a feature of malignant ovarian tumors.

Ovarian endometrioid adenocarcinoma: incidence and clinical significance of the morphologic and immunohistochemical markers of mismatch repair protein defects and tumor microsatellite instability

A subset of women with uterine cancer exhibiting defective mismatch repair (MMR) proteins and microsatellite instability (MSI) may have Lynch syndrome, which also confers a risk for colorectal cancer and other cancers in the patient and in her family. Screening algorithms based on clinical and pathologic criteria are effective in determining which patients with uterine cancer are most likely to benefit from definitive genetic testing for Lynch syndrome. Ovarian cancer, particularly endometrioid adenocarcinoma, is also associated with Lynch syndrome, although the risk is much smaller than for uterine cancer. This study evaluated whether the morphologic criteria [tumor-infiltrating lymphocytes (TILs), peritumoral lymphocytes (PTLs), dedifferentiated morphology)] currently used to screen uterine cancer for further Lynch syndrome testing can be applied to ovarian cancer. Among 71 patients with pure ovarian endometrioid adenocarcinoma treated at a single institution, 13% had a tumor with TILs, 3% had PTLs, and none had dedifferentiated morphology. Overall, 10% of tumors had abnormal MMR protein status, defined as complete immunohistochemical loss of expression of MLH1, MSH2, MSH6, and/or PMS2. Each of these tumors with abnormal MMR status demonstrated MSI using a polymerase chain reaction-based assay evaluating 5 mononucleotide repeat markers. No relationship was found between patient age, TILs, PTLs, or a spectrum of other morphologic variables and MMR protein status/MSI. Only 1/7 tumors with abnormal MMR/MSI had TILs/PTLs. Among 14 patients who died, 12 (86%) had normal MMR status. Among 7 patients with tumors with abnormal MMR/MSI, 5 (71%) were alive without disease. Concurrent uterine tumor was present in 5/7 patients whose ovarian tumor had abnormal MMR/MSI. This study suggests that the morphologic criteria used to screen patients with uterine cancer for further Lynch syndrome testing are not applicable in patients with ovarian cancer. Although abnormal MMR/MSI did not carry prognostic value in this study, it did predict the involvement of the uterus by the tumor. Thus, in patients with ovarian endometrioid adenocarcinoma who undergo uterus-sparing surgery, abnormal MMR/MSI should prompt further diagnostic evaluation of the endometrium for tumor.

Genetic risk and gynecologic cancers

Although most gynecologic malignancies are sporadic, hereditary cancer syndromes cause a substantial portion of these cancers. Given that the diagnosis of these syndromes has prognostic and therapeutic implications for the patient, as well as preventive implications for her family members, genetic testing is now an accepted part of the management of the patient who has gynecologic cancer.

Novel germline MSH2 mutation in lynch syndrome patient surviving multiple cancers

Lynch syndrome (LS) individuals are predisposed to a variety of cancers, most commonly colorectal, uterine, urinary tract, ovarian, small bowel, stomach and biliary tract cancers. The risk of extracolonic manifestations appears to be highest in MSH2 mutations carriers.

We present a carrier case with a novel MSH2 gene mutation that clearly demonstrates the broad extent of LS phenotypic expression and highlights several important clinical aspects. Current evidence suggests that colorectal tumors from LS patients tend to have better prognoses than their sporadic counterparts, however survival benefits for other cancers encountered in LS are unclear.

In this article we describe a family with a novel protein truncating mutation of c.2388delT in the MSH2 gene, particularly focusing on one individual carrier affected with multiple primary cancers who is surviving 25 years on. Our report of multiple primary tumors occurring in the 12-25 years interval might suggest these patients do not succumb to other extracolonic cancers, provided they are regularly followed-up.

Ovarian cancer linked to Lynch syndrome typically presents as early-onset, non-serous epithelial tumors

OBJECTIVE

Heredity is a major cause of ovarian cancer and during recent years the contribution from germline mismatch repair (MMR) gene mutations linked to Lynch syndrome has gradually been recognized.

METHODS

We characterized clinical features, tumor morphology and mismatch repair defects in all ovarian cancers identified in Swedish and Danish Lynch syndrome families.

RESULTS

In total, 63 epithelial ovarian cancers developed at mean 48 (range 30-79) years of age with 47% being early stage (FIGO stage I). Histologically, endometrioid (35%) and clear cell (17%) tumors were overrepresented. The underlying MMR gene mutations in these families affected MSH2 in 49%, MSH6 in 33% and MLH1 in 17%. Immunohistochemical loss of the corresponding MMR protein was demonstrated in 33/36 (92%) tumors analyzed.

CONCLUSION

The combined data from our cohorts demonstrate that ovarian cancer associated with Lynch syndrome typically presents at young age as early-stage, non-serous tumors, which implicates that a family history of colorectal and endometrial cancer should be specifically considered in such cases.

Hereditary Carcinomas of the Ovary, Fallopian Tube, and Peritoneum

Approximately 10% of ovarian cancers are associated with inherited germline mutations, most commonly of the BRCA1 or BRCA2 genes. The majority of BRCA1 and BRCA2 cancers are high-grade serous carcinomas diagnosed at an advanced stage, and there are as yet no histologic features that distinguish these tumors from sporadic serous cancers. Many women identified as being at high genetic risk undergo prophylactic salpingo-oophorectomy, and careful histopathological examination of these specimens may identify occult carcinoma, frequently in the distal fallopian tube. In addition, serous cancer precursors, including tubal intraepithelial carcinoma, have been increasingly recognized in distal and fimbrial epithelium. Little has been documented to date of the histopathological features of the cancers associated with the hereditary nonpolyposis colon cancer syndrome, but it appears these ovarian cancers may include a variety of histologic types, and in contrast to the BRCA cancers, are low grade and early stage.

Germline genetic variation, cancer outcome, and pharmacogenetics

Studies of the role of germline or inherited genetic variation on cancer outcome can fall into three distinct categories. First, the impact of highly penetrant but lowly prevalent mutations of germline DNA on cancer prognosis has been studied extensively for BRCA1 and BRCA2 mutations as well as mutations related to hereditary nonpolyposis colorectal cancer syndrome. These mainly modest-sized analyses have produced conflicting results. Although some associations have been observed, they may not be independent of other known clinical or molecular prognostic factors. Second, the impact of germline polymorphisms on cancer prognosis is a burgeoning field of research. However, a deeper understanding of potentially confounding somatic changes and larger multi-institutional, multistage studies may be needed before consistent results are seen. Third, research examining the impact of germline genetic variation on differential treatment response or toxicity (pharmacogenetics) has produced some proof-of-principle results. Putative germline pharmacogenetic predictors of outcome include DPYD polymorphisms and fluorouracil toxicity, UGT1A1 variation and irinotecan toxicity, and CYP2D6 polymorphisms and tamoxifen efficacy, with emerging data on predictors of molecularly targeted or biologic drugs. Here we review data pertaining to these germline outcome and germline toxicity relationships.

Review of the Lynch syndrome: history, molecular genetics, screening, differential diagnosis, and medicolegal ramifications

More than one million patients will manifest colorectal cancer (CRC) this year of which, conservatively, approximately 3% (approximately 30,700 cases) will have Lynch syndrome (LS), the most common hereditary CRC predisposing syndrome. Each case belongs to a family with clinical needs that require genetic counseling, DNA testing for mismatch repair genes (most frequently MLH1 or MSH2) and screening for CRC. Colonoscopy is mandated, given CRC's proximal occurrence (70-80% proximal to the splenic flexure). Due to its early age of onset (average 45 years of age), colonoscopy needs to start by age 25, and because of its accelerated carcinogenesis, it should be repeated every 1 to 2 years through age 40 and then annually thereafter. Should CRC occur, subtotal colectomy may be necessary, given the marked frequency of synchronous and metachronous CRC. Because 40-60% of female patients will manifest endometrial cancer, tailored management is essential. Additional extracolonic cancers include ovary, stomach, small bowel, pancreas, hepatobiliary tract, upper uroepithelial tract, brain (Turcot variant) and sebaceous adenomas/carcinomas (Muir-Torre variant). LS explains only 10-25% of familial CRC.

Hereditary non-polyposis colorectal cancer or Lynch syndrome: the gynaecological perspective

PURPOSE OF REVIEW

Hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome is characterized by a number of other cancers including colorectal, endometrial and ovarian cancer. This review covers the gynaecological aspects of managing women with HNPCC: diagnostic criteria, molecular tests for diagnosis, cancer risks and different strategies for surveillance and prevention.

RECENT FINDINGS

Studies correcting for ascertainment bias found slightly lower penetrance estimates than those obtained from high-risk families. HNPCC linked ovarian cancer presents at an earlier age and stage and has similar survival rates as sporadic cancer. In endometrial tumours, microsatellite instability or immunohistochemistry has limited effectiveness in selecting individuals for genetic testing, due to molecular differences. Population-based data indicate that a significant proportion of mismatch repair gene carriers would be missed by current clinical criteria. Effective risk prediction models complement clinical risk assessment. Effectiveness of screening is unproven and prophylactic surgery is the best preventive option for women who have completed their families. Multimodal screening protocols from the age of 30-35 years are being evaluated.

SUMMARY

Risk of endometrial cancer in women with Lynch syndrome is as high as the risk of colorectal cancer. Further research is needed to identify the appropriate strategy for clinical risk assessment and optimize screening. A multidisciplinary approach is necessary to manage these women.

Management of extracolonic tumours in patients with Lynch syndrome

Hereditary nonpolyposis colorectal cancer, or Lynch syndrome, is responsible for 2-3% of all colorectal cancers. Lynch syndrome is also associated with a high risk of extracolonic cancers, including endometrial, stomach, small bowel, pancreas, biliary tract, ovary, urinary tract, brain, and skin cancer. In this Review, we discuss the risks, surveillance tests, and guidelines for the management of extracolonic tumours associated with Lynch syndrome. For all types of extracolonic cancer, evidence supporting surveillance is scarce. A benefit of surveillance is evident only for endometrial cancer, where transvaginal ultrasound and endometrial sampling detect tumours in early stages. Surveillance is generally recommended for urinary tract and gastric cancer, especially in families with more than one member with these types of cancer. For the other types of cancer, surveillance is typically not recommended. Prophylactic hysterectomy and bilateral salpingo-oophorectomy should be considered for women with Lynch syndrome who are past childbearing age, especially during surgery for colorectal cancer. No data show efficacy of chemopreventive drugs in reducing the risk of extracolonic cancers for patients with Lynch syndrome.

Genetic testing in gastroenterology: Lynch syndrome

Lynch syndrome/Hereditary non-polyposis colorectal cancer is caused by inherited germline mutations in mismatch repair (MMR) genes, and accounts for 2-5% of colorectal cancers (CRC) . It is characterized by young onset CRC and an increased risk for gynaecologic, urinary tract and gastrointestinal cancers. Family history evaluation is crucial in the early identification of individuals at risk for Lynch syndrome. Individuals whose family history includes multiple relatives with cancer, two or more primary cancers, or component tumours diagnosed at a young age, should undergo genetic evaluation for Lynch syndrome. Guidelines recommend initial evaluation of the tumour with immunohistochemistry or microsatellite instability testing followed by germline testing for mutations in MMR genes in those with abnormal results. Genetic test results can guide screening recommendations for patients and their families. However, results are not always conclusive and in such cases recommendations for cancer screening should be individualized on the basis of personal and family history.

Hereditary ovarian carcinoma: heterogeneity, molecular genetics, pathology, and management

Hereditary ovarian cancer accounts for at least 5% of the estimated 22,000 new cases of this disease during 2009. During this same time, over 15,000 will die from malignancy ascribed to ovarian origin. The bulk of these hereditary cases fits the hereditary breast-ovarian cancer syndrome, while virtually all of the remainder will be consonant with the Lynch syndrome, disorders which are autosomal dominantly inherited. Advances in molecular genetics have led to the identification of BRCA1 and BRCA2 gene mutations which predispose to the hereditary breast-ovarian cancer syndrome, and mutations in mismatch repair genes, the most common of which are MSH2 and MLH1, which predispose to Lynch syndrome. These discoveries enable relatively certain diagnosis, limited only by their variable penetrance, so that identification of mutation carriers through a comprehensive cancer family history might be possible. This paper reviews the subject of hereditary ovarian cancer, with particular attention to its molecular genetic basis, its pathology, and its phenotypic/genotypic heterogeneity.

Systematic review and meta-analysis of ovarian cancers: estimation of microsatellite-high frequency and characterization of mismatch repair deficient tumor histology

PURPOSE

A meta-analytic approach was used to estimate the frequency of: (a) microsatellite instability-high (MSI-H) phenotype in unselected ovarian cancers and (b) various histologic subtypes of mismatch repair (MMR)-deficient epithelial ovarian cancers.

METHODS

A systematic search of the Medline electronic database was conducted to identify articles published between January 1, 1966, and December 31, 2007, that examined MMR deficiency in ovarian cancers. Data were extracted on the study population, sample size, MSI-H frequency, and histology of MMR-deficient ovarian tumors.

RESULTS

The pooled proportion of MSI-H ovarian cancers was 0.12 [95% confidence interval (CI), 0.08-0.17] from 18 studies with 977 cases. The proportion of histologic subtypes in the pooled analysis from 15 studies with 159 cases was serous at 0.32 (95% CI, 0.20-0.44), mucinous at 0.19 (95% CI, 0.12-0.27), endometrioid at 0.29 (95% CI, 0.22-0.36), clear cell at 0.18 (95% CI, 0.09-0.28), and mixed at 0.24 (95% CI, 0.07-0.47). There was significant heterogeneity between studies.

CONCLUSIONS

The frequency of the MSI-H phenotype in unselected ovarian cancers approximates 12%. MMR-deficient ovarian cancers also seem to be characterized by an overrepresentation of nonserous histologic subtypes. Knowledge of histologic subtype may aid clinicians in identifying the relatively large proportion of ovarian cancers due to MMR defects; such knowledge has potential implications for medical management.

A review of the clinical relevance of mismatch-repair deficiency in ovarian cancer

Ovarian cancer ranks fifth in both cancer incidence and mortality among women in the United States. Defects in the mismatch-repair (MMR) pathway that arise through genetic and/or epigenetic mechanisms may be important etiologically in a reasonable proportion of ovarian cancers. Genetic mechanisms of MMR dysfunction include germline and somatic mutations in the MMR proteins. Germline mutations cause hereditary nonpolyposis colorectal cancer (HNPCC), which is the third most common cause of inherited ovarian cancer after BRCA1 and BRCA2 mutations. An epigenetic mechanism known to cause inactivation of the MMR system is promoter hypermethylation of 1 of the MMR genes, mutL homolog 1 (MLH1). Various laboratory methods, in addition to clinical and histopathologic criteria, can be used to identify MMR-deficient ovarian cancers. Such methods include microsatellite instability analysis, immunohistochemistry, MLH1 promoter hypermethylation testing, and germline mutation analysis. In this review, the authors describe the existing literature regarding the molecular, clinical, and histologic characteristics of MMR-deficient ovarian cancers along with the possible effect on survival and treatment response. By further defining the profile of MMR-deficient ovarian cancers and their associated etiologic mechanisms, there may be a greater potential to distinguish between those of hereditary and sporadic etiology. The ability to make such distinctions may be of diagnostic, prognostic, and therapeutic utility.

Syndromic colon cancer: lynch syndrome and familial adenomatous polyposis

Colon cancer, the third leading cause of mortality from cancer in the United States, afflicts about 150,000 patients annually. More than 10% of these patients exhibit familial clustering. The most common and well characterized of these familial colon cancer syndromes is hereditary nonpolyposis colon cancer syndrome (Lynch syndrome), which accounts for about 2% to 3% of all cases of colon cancer in the United States. We review the current knowledge of familial cancer syndromes, with an emphasis on Lynch syndrome and familial adenomatous polyposis.

Two novel germline mutations of MLH1 and investigation of their pathobiology in hereditary non-polyposis colorectal cancer families in China

AIM: To detect germline mutations of MLH1, and investigate microsatellite instability and expression of MLH1 in tumor tissues of hereditary non-polyposis colorectal cancer (HNPCC) with two novel germline mutations, and further investigate the pathobiology of the two novel mutations of MLH1.

METHODS: RNA was extracted from the peripheral blood of 12 patients from 12 different families that fulfilled the Amsterdam II Criteria for HNPCC. Germline mutations of MLH1 were determined by RT-PCR, followed by cDNA sequencing analysis. PCR-GeneScan analysis was used to investigate microsatellite instability with a panel of five microsatellite markers (BAT26, BAT25, D5S346, D2S123 and mfd15), along with immunohistochemical staining to detect the expression of MLH1 protein in two patients' tumor tissues with novel mutations.

RESULTS: Three germline mutations were found in four patients, one of the mutations has previously been reported, but the other two, CGC→TGC at codon 217 of exon 8 and CCG→CTG at codon 581 of exon 16, have not been reported. The two patients' tumor tissues with novel mutations had high-frequency microsatellite instability that showed more than two unstable loci, and both tumors lost their MLH1 protein expression.

CONCLUSION: The two novel germline mutations of MLH1 in HNPCC families i.e. CGC→TGC at codon 217 of exon 8 and CCG→CTG at codon 581 of exon 16, are very likely to have pathological significance.

Review article: The Lynch syndrome (hereditary nonpolyposis colorectal cancer)

BACKGROUND

The most common inherited colorectal cancer syndrome is the Lynch syndrome (HNPCC) which is characterized by the development of colorectal, endometrial, and other cancers and the presence of microsatellite instability (MSI) in tumours. The syndrome is due to a mutation in one of the mismatch repair (MMR) genes: MSH2, MLH1, MSH6 and PMS2.

AIMS

To evaluate the clinical features of the Lynch syndrome and to assess the tools that are available for the identification of families with this syndrome.

METHODS

A systematic literature search using PubMed and reference lists of retrieved articles was performed.

RESULTS

The review provides an update of the clinical phenotype of the Lynch syndrome. Until recently, the Amsterdam criteria were the most important tool for the identification of Lynch syndrome. Nowadays, the Bethesda guidelines are more widely used. These guidelines describe all clinical conditions in which a search for MSI indicated. Both MSI-analysis as well as immunohistochemical analysis of the MMR-proteins are appropriate to identify patients with a high probability of carrying a MMR-gene mutation.

CONCLUSION

All specialists that are involved in the treatment of cancer patients should know the Bethesda criteria in order to identify all families suspected of the Lynch syndrome.

Ovarian cancer at young age: the contribution of mismatch-repair defects in a population-based series of epithelial ovarian cancer before age 40

At least one of ten patients with ovarian cancer is estimated to develop their tumor because of heredity with the breast and ovarian cancer syndrome due to mutations in the BRCA1 and BRCA2 genes and hereditary nonpolyposis colorectal cancer (HNPCC) being the major genetic causes. Cancer at young age is a hallmark of heredity, and ovarian cancers associated with HNPCC have been demonstrated to develop at a particularly early age. We used the Swedish Cancer Registry to identify a population-based series of 98 invasive epithelial ovarian cancers that developed before 40 years. Mucinous and endometrioid cancers were overrepresented and were diagnosed in 27% and 16% of the tumors, respectively. Immunostaining using antibodies against MLH1, PMS2, MSH2, and MSH6 was used to assess the mismatch-repair status and revealed loss of expression of MLH1/PMS2 in two cases, loss of MSH2/MSH6 in one case, and loss of MSH6 only in three tumors. A microsatellite instability-high phenotype was verified in five of six tumors. Based on the identified mutations and family history of cancer, several of these individuals are likely to be affected by HNPCC. We conclude that although the causes of the vast majority of epithelial ovarian cancer at young age are unknown, HNPCC should be considered because of the high risk of metachronous colorectal cancer in the individual and the possibility of preventing additional cancers in the family through control programs.