Clinicopathological features and management of cancers in lynch syndrome

Lynch Syndrome: From Carcinogenesis to Prevention Interventions

Simple Summary

Promoting proper preventive interventions to reduce morbidity and mortality is one of the most important challenges pertaining to inherited conditions. Lynch syndrome (LS) is an inherited disorder that predisposes to several kinds of tumor and is responsible for a relevant proportion of human colorectal and endometrial cancers. Recent knowledge has allowed for a better understanding of the genetic cause, pathogenesis, underlying immunological mechanisms, epidemiological distribution, and prevalence of this disease. This opens up unpredictable perspectives of translating such knowledge into validated programs for prevention and surveillance, in order to reduce the health impact of this disease through medical interventions before cancer development. In our review, we summarize the updated guidelines of the screening, surveillance, and risk-reducing strategies for LS patients. Moreover, we present novel opportunities in the treatment and prevention of LS patients through harnessing the immune system using immunocheckpoint inhibitors and vaccines.

Abstract

Lynch syndrome (LS) is the most common inherited disorder responsible for an increased risk of developing cancers at different sites, most frequently in the gastrointestinal and genitourinary tracts, caused by a germline pathogenic variant affecting the DNA mismatch repair system. Surveillance and risk-reducing procedures are currently available and warranted for LS patients, depending on underlying germline mutation, and are focused on relevant targets for early cancer diagnosis or primary prevention. Although pharmacological approaches for preventing LS-associated cancer development were started many years ago, to date, aspirin remains the most studied drug intervention and the only one suggested by the main surveillance guidelines, despite the conflicting findings. Furthermore, we also note that remarkable advances in anticancer drug discovery have given a significant boost to the application of novel immunological strategies such as immunocheckpoint inhibitors and vaccines, not only for cancer treatment, but also in a preventive setting. In this review, we outline the clinical, biologic, genetic, and morphological features of LS as well as the recent three-pathways carcinogenesis model. Furthermore, we provide an update on the dedicated screening, surveillance, and risk-reducing strategies for LS patients and describe emerging opportunities of harnessing the immune system.

Hereditary Gynecologic Cancer Syndromes - A Narrative Review

Hereditary cancer syndromes are defined as syndromes, where the genetics of cancer are the result of low penetrant polymorphisms or of a single gene disorder inherited in a mendelian fashion. During the last decade, compelling evidence has accumulated that approximately 5-10% of all cancers could be attributed to hereditary cancer syndromes. A tremendous progress has been made over the last decade in the evaluation and management of these syndromes. However, hereditary syndromes associated with gynecologic malignancies still present significant challenge for oncogynecologists. Oncogynecologists tend to pay more attention to staging, histological type and treatment options of gynecological cancers than thinking of inherited cancers and taking a detailed family history. Moreover, physicians should also be familiar with screening strategies in patients with inherited gynecological cancers. Lynch syndrome and hereditary breast-ovarian cancer syndrome are the most common and widely discussed syndromes in medical literature. The aim of the present review article is to delineate and emphasize the majority of hereditary gynecological cancer syndromes, even these, which are rarely reported in oncogynecology. The following inherited cancers are briefly discussed: Lynch syndrome; "site-specific" ovarian cancer and hereditary breast-ovarian cancer syndrome; Cowden syndrome; Li-Fraumeni syndrome; Peutz-Jeghers syndrome; ataxia-telangiectasia; DICER1- syndrome; gonadal dysgenesis; tuberous sclerosis; multiple endocrine neoplasia type I, II; hereditary small cell carcinoma of the ovary, hypercalcemic type and hereditary undifferentiated uterine sarcoma; hereditary diffuse gastric cancer and MUTYH-associated polyposis. Epidemiology, pathogenesis, diagnosis, pathology and screening of these syndromes are discussed. General treatment recommendations are beyond the scope of this review.

Molecular Pathogenesis of Cholangiocarcinoma

BACKGROUND

Cholangiocarcinomas are a heterogeneous group of malignancies arising from a number of cells of origin along the biliary tree. Although most cases in Western countries are sporadic, large population-based studies have identified a number of risk factors. This review summarises the evidence behind reported risk factors and current understanding of the molecular pathogenesis of cholangiocarcinoma, with a focus on inflammation and cholestasis as the driving forces in cholangiocarcinoma development.

RISK FACTORS FOR CHOLANGIOCARCINOGENESIS

Cholestatic liver diseases (e.g. primary sclerosing cholangitis and fibropolycystic liver diseases), liver cirrhosis, and biliary stone disease all increase the risk of cholangiocarcinoma. Certain bacterial, viral or parasitic infections such as hepatitis B and C and liver flukes also increase cholangiocarcinoma risk. Other risk factors include inflammatory disorders (such as inflammatory bowel disease and chronic pancreatitis), toxins (e.g. alcohol and tobacco), metabolic conditions (diabetes, obesity and non-alcoholic fatty liver disease) and a number of genetic disorders.

MOLECULAR PATHOGENESIS OF CHOLANGIOCARCINOMA

Regardless of aetiology, most risk factors cause chronic inflammation or cholestasis. Chronic inflammation leads to increased exposure of cholangiocytes to the inflammatory mediators interleukin-6, Tumour Necrosis Factor-ɑ, Cyclo-oxygenase-2 and Wnt, resulting in progressive mutations in tumour suppressor genes, proto-oncogenes and DNA mismatch-repair genes. Accumulating bile acids from cholestasis lead to reduced pH, increased apoptosis and activation of ERK1/2, Akt and NF-κB pathways that encourage cell proliferation, migration and survival. Other mediators upregulated in cholangiocarcinoma include Transforming Growth Factor-β, Vascular Endothelial Growth Factor, Hepatocyte Growth Factor and several microRNAs. Increased expression of the cell surface receptor c-Met, the glucose transporter GLUT-1 and the sodium iodide symporter lead to tumour growth, angiogenesis and cell migration. Stromal changes are also observed, resulting in alterations to the extracellular matrix composition and recruitment of fibroblasts and macrophages that create a microenvironment promoting cell survival, invasion and metastasis.

CONCLUSION

Regardless of aetiology, most risk factors for cholangiocarcinoma cause chronic inflammation and/or cholestasis, leading to the activation of common intracellular pathways that result in reactive cell proliferation, genetic/epigenetic mutations and cholangiocarcinogenesis. An understanding of the molecular pathogenesis of cholangiocarcinoma is vital when developing new diagnostic biomarkers and targeted therapies for this disease.

Molecular and Pathological Features of Gastric Cancer in Lynch Syndrome and Familial Adenomatous Polyposis

Lynch syndrome (LS) and familial adenomatous polyposis (FAP) are autosomal dominant hereditary diseases caused by germline mutations leading to the development of colorectal cancer. Moreover, these mutations result in the development of a spectrum of different tumors, including gastric cancers (GCs). Since the clinical characteristics of GCs associated with LS and FAP are not well known, we investigated clinical and molecular features of GCs occurring in patients with LS and FAP attending our Institution. The Hereditary Tumor Registry was established in 1994 at the Department of Oncologic Gastroenterology, CRO Aviano National Cancer Institute, Italy. It includes 139 patients with LS and 86 patients with FAP. Patients were recruited locally for prospective surveillance. Out of 139 LS patients, 4 developed GC—3 in the presence of helicobacter pylori infection and 1 on the background of autoimmune diseases. All GCs displayed a high microsatellite instability (MSI-H) and loss of related mismatch repair (MMR) protein. One of the FAP patients developed a flat adenoma, displaying low-grade dysplasia at the gastric body, and another poorly differentiated adenocarcinoma with signet ring cells like Krukenberg without HP infection. LS carriers displayed a risk of GC. The recognition of HP infection and autoimmune diseases would indicate those at higher risk for an endoscopic surveillance. Regarding FAP, the data suggested the need of suitable endoscopic surveillance in long survivals with diffuse fundic gland polyps.

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.

The analysis of microsatellite instability in extracolonic gastrointestinal malignancy

Microsatellite instability (MSI) is a genetic feature of sporadic and familial cancers of multiple sites and is related to defective mismatch repair (MMR) protein function. Lynch syndrome (LS) is a familial form of MMR deficiency that may present with a spectrum of MSI positive cancers including gastrointestinal (GI) malignancies. The incidence of high level MSI (MSI-H) in colorectal carcinoma is well defined in both familial and sporadic cases and these tumours portend a better overall prognosis in colorectal carcinoma (CRC). There are certain morphological features that suggest MSI-H CRC and international guidelines have been established for the evaluation of MSI in CRC. The prevalence and morphological features of extracolonic GI MSI-H tumours are less well documented. Furthermore, it is unclear whether the guidelines for the assessment of MSI in CRC are appropriate for application to extracolonic GI malignancies. This review aims to summarise the recent literature on MSI in extracolonic LS-related GI tract malignancies with special attention to the assessment of the MMR system by evaluation of specific microsatellite markers and/or immunohistochemical evaluation of MMR protein expression. The reported prevalence of sporadic and LS-related MSI-H tumours along with their associated unique morphological patterns and related prognostic or therapeutic implications will be discussed.

Cancer risk in Lynch Syndrome

Lynch Syndrome, or hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant cancer predisposition syndrome caused by inactivating mutations in DNA mismatch repair genes. It accounts for 2-4 % of all incident colorectal cancers. Mutation carriers are at risk of early onset colorectal cancer, endometrial cancer, and a spectrum of other tumours. Accurate estimation of cancer risk for mutation carriers is essential for counselling, and establishing appropriate screening guidelines. This study reviews the current data on cancer risk, and emerging risk reduction strategies.