Evaluation of a combined model of Polygenic Risk Score and mismatch repair genes in the association of colorectal cancer for Norwegian cohort.

Background And Aims: Recent studies have shown that combining polygenic risk score (PRS) and carrier status for germline pathogenic variants in colorectal cancer (CRC) susceptibility genes (e.g. ) may increase the success of predicting CRC.

Incidences of colorectal adenomas and cancers under colonoscopy surveillance suggest an accelerated "Big Bang" pathway to CRC in three of the four Lynch syndromes.

Background: Colorectal cancers (CRCs) in the Lynch syndromes have been assumed to emerge through an accelerated adenoma-carcinoma pathway. In this model adenomas with deficient mismatch repair have an increased probability of acquiring additional cancer driver mutation(s) resulting in more rapid progression to malignancy. If this model was accurate, the success of colonoscopy in preventing CRC would be a function of the intervals between colonoscopies and mean sojourn time of detectable adenomas.

Delineating genotype and parent-of-origin effect on the phenotype in MSH6-associated Lynch syndrome.

Background: This study investigates the potential influence of genotype and parent-of-origin effects (POE) on the clinical manifestations of Lynch syndrome (LS) within families carrying (likely) disease-causing MSH6 germline variants.

Patients And Methods: A cohort of 1615 MSH6 variant carriers (310 LS families) was analyzed. Participants were categorized based on RNA expression and parental inheritance of the variant.

A comprehensive characterization of the spectrum of MUTYH germline pathogenic variants in Latin America.

MUTYH-Associated Polyposis (MAP) is caused by biallelic pathogenic germline variants in the MUTYH gene. However, individuals harboring monoallelic MUTYH pathogenic variants in the presence of a positive family history have been reported to have a twofold increased risk of colorectal cancer (CRC) and extra colonic cancers. Our aim was to characterize the spectrum of monoallelic and biallelic germline MUTYH pathogenic variants in Latin American patients and to describe their clinical and genetic characteristics.

Exploring Stakeholders' Perspectives on Implementing Universal Germline Testing for Colorectal Cancer: Findings From a Clinical Practice Survey.

Purpose: New guidelines recommend considering germline genetic testing for all patients with colorectal cancer (CRC). However, there is a lack of data on stakeholders' perspectives on the advantages and barriers of implementing universal germline testing (UGT). This study assessed the perspectives of members of the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer (CGA-IGC) regarding the implementation of UGT for patients with CRC, including readiness, logistics, and barriers.

A Breast Cancer Polygenic Risk Score Is Feasible for Risk Stratification in the Norwegian Population.

Background: Statistical associations of numerous single nucleotide polymorphisms with breast cancer (BC) have been identified in genome-wide association studies (GWAS). Recent evidence suggests that a Polygenic Risk Score (PRS) can be a useful risk stratification instrument for a BC screening strategy, and a PRS test has been developed for clinical use. The performance of the PRS is yet unknown in the Norwegian population.

Cancer surveillance for transgender and gender diverse patients with Lynch syndrome: a practice resource of the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer.

Transgender and gender diverse (TGD) populations with hereditary cancer syndromes face unique obstacles to identifying and obtaining appropriate cancer surveillance and risk-reducing procedures. There is a lack of care provider knowledge about TGD health management. Lynch syndrome (LS) is one of the most common hereditary cancer syndromes, affecting an estimated 1 in 279 individuals.

Current chemoprevention approaches in Lynch syndrome and Familial adenomatous polyposis: a global clinical practice survey.

Background: International chemoprevention preferences and approaches in Lynch syndrome (LS) and associated polyposis, including Familial adenomatous polyposis (FAP) and attenuated FAP (AFAP) have not been previously explored.

Aim: To describe current chemoprevention strategies for patients with LS or FAP/AFAP (referred to collectively as FAP) practiced by members of four international hereditary cancer societies through administration of a survey.

Results: Ninety-six participants across four hereditary gastrointestinal cancer societies responded to the survey.

Genetic Characterization in High-Risk Individuals from a Low-Resource City of Peru.

Background: Genetic testing for hereditary cancers is inconsistently applied within the healthcare systems in Latin America. In Peru, the prevalence and spectrum of cancer-predisposing germline variants is thus poorly characterized. Purpose: To determine the spectrum and prevalence of cancer-predisposing germline variants and variants of uncertain significance (VUS) in high-risk individuals located in a Peruvian low-resource setting city.

Patterns of germline and somatic testing after universal tumor screening for Lynch syndrome: A clinical practice survey of active members of the Collaborative Group of the Americas on Inherited Gastrointestinal Cancer.

Clinical guidelines recommend universal tumor screening (UTS) of colorectal and endometrial cancers for Lynch syndrome (LS). There are limited guidelines for how to integrate germline testing and somatic tumor testing after a mismatch repair deficient (dMMR) tumor is identified. We sought to characterize current practice patterns and barriers to preferred practice among clinical providers in high-risk cancer programs.

No Difference in Penetrance between Truncating and Missense/Aberrant Splicing Pathogenic Variants in and : A Prospective Lynch Syndrome Database Study.

Background: Lynch syndrome is the most common genetic predisposition for hereditary cancer. Carriers of pathogenic changes in mismatch repair (MMR) genes have an increased risk of developing colorectal (CRC), endometrial, ovarian, urinary tract, prostate, and other cancers, depending on which gene is malfunctioning. In Lynch syndrome, differences in cancer incidence (penetrance) according to the gene involved have led to the stratification of cancer surveillance.

European guidelines from the EHTG and ESCP for Lynch syndrome: an updated third edition of the Mallorca guidelines based on gene and gender.

Background: Lynch syndrome is the most common genetic predisposition for hereditary cancer but remains underdiagnosed. Large prospective observational studies have recently increased understanding of the effectiveness of colonoscopic surveillance and the heterogeneity of cancer risk between genotypes. The need for gene- and gender-specific guidelines has been acknowledged.