Lynch Syndrome Patients Research Articles

Segmental versus extended colectomy for colorectal cancer in patients with lynch syndrome: A systematic review and meta-analysis.

The decision to perform segmental or extended colectomy in Lynch syndrome (LS) patients with colorectal cancer (CRC) is still controversial. Therefore, this systematic review and meta-analysis aims to provide updated evidence for segmental versus extended colectomy in LS carriers with CRC. PubMed, Embase, and Cochrane Library were systematically searched for studies published until January 2024 comparing segmental and extended colectomies for CRC in patients with LS. Risk ratio (RR) was used to evaluate binary endpoints with 95% confidence intervals (CIs). Heterogeneity was assessed with the Cochran's Q test and I2 statistics. Statistical analysis was performed using the R Software, version 4.2.3. A total of 14 studies comprising 2303 LS carriers with CRC, of whom 1724 (74.9%) patients underwent segmental colectomy and 579 (25.1%) patients underwent extended colectomy. Segmental colectomy significantly increased metachronous CRC (mCRC) (RR 2.87; 95% CI 2.03-4.07; and p<0.01). There were no significant differences between groups for 5-year overall survival (OS) (RR 0.92; 95% CI 0.82-1.03; and p=0.14), 10-year OS (RR 0.99; 95% CI 0.96-1.04; and p=0.80), and mortality (RR 1.63; 95% CI 0.90-2.97; and p=0.11). There were no significant linear associations between the outcome of mCRC and age at the time of primary CRC, sex, primary CRC location, and pathogenic LS variant. In this meta-analysis, segmental colectomy significantly increased mCRC compared with extended colectomy after the first surgery for CRC in patients with LS. However, there were no significant differences between groups for 5- and 10-year OS and mortality.

Prospective Screening of Cancer Syndromes in Patients with Mesenchymal Tumors.

The etiology of most mesenchymal tumors is unknown, and knowledge about syndromes with an increased risk of tumors in bone or soft tissue is sparse. We present a prospective germline analysis of 312 patients with tumors suspected of being sarcomas at a tertiary sarcoma center. Germline and tumor whole genome sequencing, tumor transcriptome, and methylome analyses were performed. Germline pathogenic or likely pathogenic variants associated with an increased risk of tumors were detected in 24 patients (8%), of which 11 (4%) harbored a detectable second hit in the tumor. Second hits were confirmed in genes with (NF1, RB1, TP53, EXT2, and SDHC) and without (ATM, CDC73, MLH1, MSH6, POLG, and KCNQ1) known association with mesenchymal tumor predisposition. Sarcomas from two Lynch syndrome patients showed mismatch repair deficiency, predicting a treatment response to immune checkpoint inhibitors (Level 1 biomarker according to the FDA (Federal Drug Administration) and ESMO (European Society for Medical Oncology)). None of the three CHEK2 carriers had a second hit in the tumor, suggesting a weak link to sarcoma. We conclude that second-hit analyses can be used in standard of care to identify syndrome-related tumors. This approach can help distinguish true manifestations of tumor syndromes from unrelated germline findings and enhance the understanding of germline predisposition in soft tissue tumors. Prospective screening using germline whole genome sequencing should be considered when comprehensive somatic sequencing is introduced into clinical practice.

Compliance of a Tertiary Centre With Molecular Testing Strategies for Lynch Syndrome in Colorectal Cancer.

Introduction Lynch syndrome is one of the most common hereditary cancers associated with germline alterations of DNA mismatch repair genes. Recent advances have shed light on its molecular pathogenesis, leading to the development of various testing strategies. The aim of this study is to evaluate whether all colorectal adenocarcinomas undergo immunohistochemistry (IHC) and microsatellite instability (MSI) testing to identify potential Lynch syndrome patients. Methods This study evaluated the compliance of MSI and IHC testing for Lynch syndrome in a tertiary cancer research centre. All patients undergoing colorectal cancer resectionbetween April 2022 and December 2022were identified from a prospectively maintained register. The histology, MSI, and IHC testing reports for these patients were recorded to check if they were done and reported. Only patients with colorectal adenocarcinoma were included in this study. Results A total of 314 patients had colorectal cancer resections. A total of 301 were included in the study, with a median age of 65 years (IQR = 35-95). Thirteen (4.14%) patients did not have MSI and IHC testing reported on the system. Of these, eight (61.53%) did not have an MSI/IHC testing request, four (30.76%) did not have sufficient specimens to be sent for further testing, one (7.69%) had MSI and IHC testing but the final report was yet to be authorized. Out of the eight who did not have the testing done, three had early polyp cancer and one had a goblet cell adenocarcinoma. Conclusion According to the data, our hospital has a 97.45% compliance with current guidelines, not considering the insufficient sample for testing and the authorization of the final report. A more comprehensive proforma may be needed to provide a feedback loop for further MSI and IHC testing when entering data into the system. Further auditing is required to check the effectiveness of the proforma in achieving complete compliance.

Abstract B058: Nous-209 off-the-shelf vaccine targets neoantigens mutations well represented both in primary and metachronous incident CRCs from Lynch syndrome patients

Abstract Lynch Syndrome (LS) is the most common hereditary cancer syndrome, caused by germline mutations in one of the four DNA mismatch repair (MMR) genes. LS patients have a high risk to develop microsatellite instable (MSI) colorectal cancers. Tumors developed by LS carriers display high levels of microsatellite instability, which leads to the accumulation of large numbers of mutations, among which frameshift insertion/deletions (indels) within microsatellite (MS) loci are very common and shared among different tumors. When indels occur in coding genes they give rise to frameshift peptides (FSPs) with a very high potential to act as safe and potent neoantigens for a vaccine. NOUS-209 is a genetic vaccine encoding 209 neoantigens, shared across sporadic and hereditary MSI tumors, developed for interception and treatment of MSI tumors. Phase 1b trial evaluating NOUS-209 monotherapy in healthy LS carriers showed the induction of a potent and broad immune response. Here, we characterize indels encoding FSPs in a cohort of 50 incident MSI CRC from LS patients detected during routine screening (38 primary tumors; 22 metachronous tumors) by whole Exomeseq NGS. Overall, primary and metachronous tumors have a similar number of indels in coding genes. The repertoire of detected indels is only partially shared (27%) between the two categories of tumors. The 209 indels selected for the NOUS-209 vaccine are instead highly shared (95%) between primary and metachronous tumors. Moreover, the analysis of 8 patients for which both the primary and the metachronous tumor were available confirmed the presence of the 209 mutations both in the first and the second tumor. Therefore, the NOUS 209 vaccine has the potential to prevent tumor occurrence both in previvors and survivors by inducing a broad T cell immune response against recurrent FSP. Citation Format: Lorenzo De Marco, Elisa Micarelli, Joni Panula, Anna Morena D'Alise, Guido Leoni, Kalle E. Hokkanen, Eija Hämäläinen, Jukka-Pekka Mecklin, Elisa Scarselli, Toni Seppälä. Nous-209 off-the-shelf vaccine targets neoantigens mutations well represented both in primary and metachronous incident CRCs from Lynch syndrome patients [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B058.

Abstract PR-05: Nous-209 off-the-shelf vaccine targets neoantigens mutations well represented both in primary and metachronous incident CRCs from Lynch syndrome patients

Abstract PR-05: Nous-209 off-the-shelf vaccine targets neoantigens mutations well represented both in primary and metachronous incident CRCs from Lynch syndrome patients

Solitary Loss of PMS2 in a patient with Colon carcinoma

Abstract Introduction/Objective In the United States, there are about 150,000 new cases of Colorectal cancer (CRC) and about 50,000 CRC related deaths each year. Hereditary nonpolyposis colorectal cancer (Lynch Syndrome) accounts for 2% - 4% of CRC. It is characterized by germline mutations in mismatch repair (MMR) genes - MLH1, MSH2, MSH6 and PMS2. Patients with Lynch syndrome have up to an 80% lifetime risk (LTR) of CRC and up to 60% LTR of endometrial cancer. Lynch syndrome patients also have an associated LTR of ovarian cancer (38%), upper urologic tract cancer (18%), gastric cancer (13%), small bowel cancer (6%), hepatobiliary tract cancer (4%), and brain tumors (3% - usually glioblastoma). Methods/Case Report A 76-year-old man with history of moderately differentiated colorectal adenosarcoma involving the transverse colon and a recently diagnosed grade group 5 (Gleason 4 + 5) prostate adenocarcinoma, currently being managed at an outside hospital. The case was sent to UAB for DNA MMR/microsatellite instability (MSI) status evaluation testing. Immunostaining showed loss of PMS2 and intact expression of MLH1, MSH2 and MSH6. These results were confirmed by the IdyIIa MSI assay which detected microsatellite instability in 5 of 7 markers and negative for BRAF V600E variant confirming microsatellite instable tumor. Results (if a Case Study enter NA) NA Conclusion Solitary loss of PMS2 in colonic adenocarcinoma is uncommon and may be caused by an underlying germline mutation of MLH-1 or PMS2, thus could represent Lynch Syndrome. Our patient’s age doesn’t favor Lynch syndrome. Next step would be to perform MLH-1 promoter methylation to confirm sporadic nature of carcinoma. Somatic methylation of the MLH1 promoter occurs in approximately 80% of CRC with defective MMR. Prostate cancer is not currently considered a part of Lynch syndrome.

Influence of Genetic Polymorphisms on the Age at Cancer Diagnosis in a Homogenous Lynch Syndrome Cohort of Individuals Carrying the MLH1:c.1528C>T South African Founder Variant.

Background: High variability in the age at cancer diagnosis in Lynch syndrome (LS) patients is widely observed, even among relatives with the same germline pathogenic variant (PV) in the mismatch repair (MMR) genes. Genetic polymorphisms and lifestyle factors are thought to contribute to this variability. We investigated the influence of previously reported genetic polymorphisms on the age at cancer diagnosis in a homogenous LS cohort with a South African founder germline PV c.1528C>T in the MLH1 gene. Methods: A total of 359 LS variant heterozygotes (LSVH) from 60 different families were genotyped for specific genetic polymorphisms in GSTM1, GSTT1, CYP1A1, CYP17, PPP2R2B, KIF20A, TGFB1, XRCC5, TNF, BCL2, CHFR, CDC25C, ATM, TTC28, CDC25C, HFE, and hTERT genes using Multiplex Polymerase Chain Reaction and MassArray methods. Kaplan-Meier survival analysis, univariate and multivariate Cox proportional hazards gamma shared frailty models adjusted for sex were used to estimate the association between age at cancer diagnosis and polymorphism genotypes. A p-value < 0.05 after correcting for multiple testing using the Benjamini-Hochberg method was considered significant at a 95% confidence interval. Results: We identified three genotypes in the cell-cycle regulation, DNA repair, and xenobiotic-metabolism genes significantly associated with age at cancer diagnosis in this cohort. The CYP1A1 rs4646903 risk (GG) and CDC25C rs3734166 polymorphic (GA+AA) genotypes were significantly associated with an increased risk of a younger age at cancer diagnosis (Adj HR: 2.03 [1.01-4.08], p = 0.034 and Adj HR: 1.53 [1.09-2.14], p = 0.015, respectively). LSVH who were heterozygous for the XRCC5 rs1051685 SNP showed significant protection against younger age at cancer diagnosis (Adj HR: 0.69 [CI, 0.48-0.99], p = 0.043). The risk of a younger age at any cancer diagnosis was significantly high in LS carriers of one to two risk genotypes (Adj HR: 1.49 [CI: 1.06-2.09], corrected p = 0.030), while having one to two protective genotypes significantly reduced the risk of developing any cancer and CRC at a younger age (Adj HR: 0.52 [CI: 0.37-0.73], and Adj HR: 0.51 [CI: 0.36-0.74], both corrected p < 0.001). Conclusions: Polymorphism genotypes in the cell-cycle regulation, DNA repair, and xenobiotic metabolizing genes may influence the age at cancer diagnosis in a homogenous LS cohort with a South African founder germline PV c.1528C>T in the MLH1 gene.

Gender-specific differences in the development of colorectal cancer in Lynch syndrome patients-Asystematic review

Lynch syndrome (LS) is the most frequent hereditary tumor syndrome and is associated with an increased risk of colorectal cancer (CRC). While gene-specific and age-specific differences are considered in patient surveillance, gender-specific risks in the development of CRC have been reported in many studies but are not consistently documented. This systematic review aims to investigate gender-specific differences in CRC development among LS patients. Asystematic literature search following PRISMA 2020 guidelines was conducted in the PubMed, Ovid, The Cochrane Library and Web of Science databases. A total of 688 studies were screened, and 41met the inclusion criteria. Men have ahigher risk of CRC and develop CRC earlier compared to women. These findings indicate gender-specific differences in the risk of CRC among LS patients, although they do not currently justify separate surveillance strategies.

Complications of colonoscopy surveillance of patients with Lynch syndrome – 33 years of follow up

Background and study aims: Lynch syndrome (LS) is a hereditary autosomal dominant condition, with an increased lifetime risk of developing malignancies including colorectal cancer (CRC). Current guidelines differ in recommended colonoscopy-surveillance intervals from 1 to 2 years. Although colonoscopy is considered a safe procedure, there are risks of severe adverse events (SAEs), such as perforation and bleeding, as well as adverse events (AEs), such as abdominal discomfort and post-colonoscopy gastrointestinal infections. Colonoscopy-related bleeding and perforation rates have been reported 0.17% and 0.11%, respectively. However, there are insufficient data regarding complications of colonoscopy-surveillance for LS patients. This study aims to investigate the risk of AEs among LS patients during colonoscopy in the Stockholm region. Patients and methods: This retrospective cohort study includes 351 LS patients undergoing endoscopic surveillance at the Karolinska University Hospital, August 1989 – April 2021. Data from endoscopic surveillance colonoscopies were extracted from patients’ medical records. Results: Of 1873 endoscopies in 351 LS patients, 12 complications (AEs) were documented within 30 days (0.64%) and with a total of 3 bleedings (SAEs, 0.16%). No perforations were identified. Conclusion: Colonoscopy surveillance for LS patients shows a comparatively low risk of AEs per-examination. Colonoscopy complications per-patient, including both SAEs and AEs, show a significantly higher risk. Colonoscopy complications only including SAEs, show a comparatively low risk. Understanding the lifetime risk of surveillance-related colonoscopy complications is important when designing targeted surveillance programmes.

High Probability of Lynch Syndrome Among Colorectal Cancer Patients Is Associated With Higher Occurrence of KRAS and PIK3CA Mutations.

In Indonesia, early-onset colorectal cancer (EOCRC) rates are higher in patients < 50 years old compared to Western populations, possibly due to a higher frequency of Lynch syndrome (LS) in CRC patients. We aimed to examine the association of KRAS and PIK3CA mutations with LS. In this retrospective cross-sectional single-center study, the PCR-HRM-based test was used for screening of microsatellite instability (MSI) mononucleotide markers (BAT25, BAT26, BCAT25, MYB, EWSR1), MLH1 promoter methylation, and oncogene mutations of BRAF (V600E), KRAS (exon 2 and 3), and PIK3CA (exon 9 and 20) in FFPE DNA samples. All the samples (n = 244) were from Dr. Sardjito General Hospital Yogyakarta, Indonesia. KRAS and PIK3CA mutations were found in 151/244 (61.88%) and 107/244 (43.85%) of samples, respectively. KRAS and PIK3CA mutations were significantly associated with MSI status in 32/42 (76.19%) and 25/42 (59.52%) of samples, respectively. KRAS mutation was significantly associated with LS status in 26/32 (81.25%) of samples. The PIK3CA mutation was present in a higher proportion in LS samples of 19/32 (59.38%), but not statistically significant. Clinicopathology showed that KRAS mutation was significantly associated with right-sided CRC and higher histology grade in 39/151 (25.83%) and 24/151 (16.44%) samples, respectively. PIK3CA mutation was significantly associated with female sex and lower levels of tumor-infiltrating lymphocytes in 62/107 (57.94%) and 26/107 (30.23%) samples, respectively. KRAS and PIK3CA mutations did not significantly affect overall survival (120 months) in LS and non-LS patients. The high probability of LS in Indonesian CRC patients is associated with KRAS and PIK3CA mutations.

Universal Lynch Syndrome Screening in Colorectal Cancer: A 5-Year Experience of a Portuguese Pathology Department.

Lynch syndrome (LS) is a prevalent genetic condition associated with colorectal cancer (CRC). Accurate identification of LS patients is challenging, and a universal tumor screening approach has been recommended. We present the methodology and results of universal LS screening in our hospital's Pathology Department. This retrospective study analyzed CRC tumors from a 5-year period (2017-2021). Immunohistochemistry was used to assess MMR protein expression, followed by BRAF V600E analysis and MLH1 promoter methylation. Statistical analysis examined associations between clinicopathologic variables MMR status and LS-suspected tumors. The study analyzed 939 colorectal carcinomas, with 8.7% exhibiting mismatch repair (MMR) deficiency, significantly lower than previous research. After applying the algorithm, 24 LS-suspected cases were identified, accounting for 2.6% of tested patients and 29.3% of MMR-deficient tumors. Our study establishes the feasibility of universal testing for all new cases of CRC in detecting individuals at risk for LS, even in the absence of clinical information. To gain a comprehensive understanding of the MMR status in our population, further investigations are warranted.

Investigating genetic counselors' communication with Lynch syndrome patients about cascade testing: Barriers, facilitators, and strategies.

Cascade testing is an imperative process to engage Lynch syndrome patients' at-risk relatives in early cancer risk reduction interventions. How genetic counselors communicate about cascade testing is crucial to patients' intentions of and actual involvement in family communication. Based on data from 20 interviews with genetic counselors, this qualitative study examined their perceptions of barriers and facilitators of offering cascade testing to at-risk relatives and the specific communication strategies they use to discuss cascade testing with patients. We identified patient-level, genetic counselor-level, and system-level barriers and facilitators of having discussions with Lynch syndrome patients about cascade testing. The qualitative data also revealed four prominent communication strategies that genetic counselors use for such discussions: build rapport, reframe the benefits of family communication, adapt communication, and provide various resources. These findings highlight genetic counselors' needs of practical and structural support to facilitate their communication about cascade testing, especially when patients are hesitant or lack resources or skills to notify at-risk relatives about cascade testing.

Quality of endoscopic surveillance of Lynch syndrome patients in a Swedish cohort.

Background and study aims Risk factors for colorectal cancer (CRC) in Lynch syndrome (LS) include sex, age, smoking, high body mass index (BMI), surveillance interval length, and risk genotype. The Boston Bowel Preparation Scale (BBPS) produces a standardized bowel cleanliness rating. A low BBPS score might be a risk factor for missed early lesions. The aim of this study was to investigate the correlation between BBPS score and adenoma detection (with known risk factors for CRC) and surveillance interval with CRC detection in LS patients. Methods A retrospective cohort study including 366 LS patients with 1,887 colonoscopies under surveillance in Stockholm, Sweden from 1989 to 2021 was conducted. Associations were tested using linear and logistic regression. Results We found no association between BBPS score and number of adenomas detected. A low BBPS score was found to be associated with older age (regression coefficient (coeff) -0.015; 95% confidence interval [CI] -0.026 to -0.004; P = 0.007) and obesity (coeff = -0.48; 95% CI: -0.89 to -0.062; P = 0.024). A higher number of detected adenomas was associated with older age (coeff = 0.008; 95% CI 0.004 to 0.012; P < 0.001), male sex (coeff = 0.097; 95% CI 0.008 to 0.19; P = 0.033) and CRC (coeff = 0.28; 95% CI 0.061 to 0.50; P = 0.012). Surveillance interval length was not significant in CRC detection. Conclusions Bowel cleanliness was not associated with adenoma detection and was less likely achieved in patients who were older and had higher BMI. Adenoma detection was associated with older age and male sex. The results indicate the need for better adherence to guidelines and attention to older age groups, men, and patients with obesity.

Lynch Syndrome and Thyroid Nodules: A Single Center Experience.

Lynch syndrome (LS) is a genetic disease with increased risk of colorectal cancer and other malignancies. There are few reported cases of thyroid cancer in LS patients. The aim of this study is to investigate the presence of thyroid nodules in LS patients and to explore their association with the genetic features of the disease. A retrospective and descriptive analysis was conducted to include all LS patients followed at the CEMAD (Centro Malattie Apparato Digerente) of Fondazione Policlinico Universitario A. Gemelli IRCCS. The characteristics of LS disease, gene mutations, and previous history of thyroid disease were evaluated. Majority of patients underwent thyroid ultrasound (US), and nodule cytology was performed when needed. Of a total of 139 patients with LS, 110 patients were included in the study. A total of 103 patients (74%) underwent thyroid ultrasound examinations, and 7 patients (5%) had a previous history of thyroid disease (cancer or multinodular goiter). The mean age was 51.9 years. Thyroid nodules were found in 62 patients (60%) who underwent US, and 9 of them (14%) had suspicious features of malignancy, inducing a fine-needle aspiration biopsy. A cytologic analysis classified 7 of 9 cases (78%) as TIR2 and 2 (22%) as TIR3a. Between patients with nodular thyroid disease (single nodule, multinodular goiter, and cancer), most of them (25 patients, 36% of total) were carriers of the MSH6 mutation, while 22 (32%), 17 (24%), and 5 (7%) had MSH2, MLH1, and PMS2 mutations, respectively. A high prevalence of thyroid nodules was found in patients with LS, especially in MSH6-carrying patients. Performing at least one thyroid ultrasound examination is suggested for the detection of nodular thyroid disease in LS patients. Systematic investigations are needed to estimate their prevalence, features, and risk of malignant transformation.

Functional analysis of MMR gene VUS from potential Lynch syndrome patients.

Lynch syndrome is caused by inactivating variants in DNA mismatch repair genes, namely MLH1, MSH2, MSH6 and PMS2. We have investigated five MLH1 and one MSH2 variants that we have identified in Turkish and Tunisian colorectal cancer patients. These variants comprised two small deletions causing frameshifts resulting in premature stops which could be classified pathogenic (MLH1 p.(His727Profs*57) and MSH2 p.(Thr788Asnfs*11)), but also two missense variants (MLH1 p.(Asn338Ser) and p.(Gly181Ser)) and two small, in-frame deletion variants (p.(Val647-Leu650del) and p.(Lys678_Cys680del)). For such small coding genetic variants, it is unclear if they are inactivating or not. We here provide clinical description of the variant carriers and their families, and we performed biochemical laboratory testing on the variant proteins to test if their stability or their MMR activity are compromised. Subsequently, we compared the results to in-silico predictions on structure and conservation. We demonstrate that neither missense alteration affected function, while both deletion variants caused a dramatic instability of the MLH1 protein, resulting in MMR deficiency. These results were consistent with the structural analyses that were performed. The study shows that knowledge of protein function may provide molecular explanations of results obtained with functional biochemical testing and can thereby, in conjunction with clinical information, elevate the evidential value and facilitate clinical management in affected families.

Corrigendum to ‘‘Risk of Gastric Cancer and Utility of Endoscopic Screening for Lynch Syndrome Patients’’

Corrigendum to ‘‘Risk of Gastric Cancer and Utility of Endoscopic Screening for Lynch Syndrome Patients’’

Constitutional mismatch repair deficiency mimicking Lynch syndrome is associated with hypomorphic mismatch repair gene variants

Lynch syndrome (LS) and constitutional mismatch repair deficiency (CMMRD) are distinct cancer syndromes caused, respectively, by mono- and bi-allelic germline mismatch repair (MMR) variants. LS predisposes to mainly gastrointestinal and genitourinary cancers in adulthood. CMMRD predisposes to brain, haematological, and LS-spectrum cancers from childhood. Two suspected LS patients with first cancer diagnosis aged 27 or 38 years were found to be homozygous for an MMR (likely) pathogenic variant, MSH6 c.3226C>T (p.(Arg1076Cys)), or variant of uncertain significance (VUS), MLH1 c.306G>A (p.(Glu102=)). MLH1 c.306G>A was shown to cause leaky exon 3 skipping. The apparent genotype-phenotype conflict was resolved by detection of constitutional microsatellite instability in both patients, a hallmark feature of CMMRD. A hypomorphic effect of these and other variants found in additional late onset CMMRD cases, identified by literature review, likely explains a LS-like phenotype. CMMRD testing in carriers of compound heterozygous or homozygous MMR VUS may find similar cases and novel hypomorphic variants. Individualised management of mono- and bi-allelic carriers of hypomorphic MMR variants is needed until we better characterise the associated phenotypes.

Novel insights into tumorigenesis revealed by molecular analysis of Lynch syndrome cases with multiple colorectal tumors.

Lynch syndrome (LS) is an autosomal dominant multi-organ cancer syndrome with a high lifetime risk of cancer. The number of cumulative colorectal adenomas in LS does not generally exceed ten, and removal of adenomas via routine screening minimizes the cancer burden. However, abnormal phenotypes may mislead initial diagnosis and subsequently cause suboptimal treatment. Currently, there is no standard guide for the care of multiple colorectal adenomas in LS individuals. We aimed to shed insight into the molecular features and reasons for multiplicity of adenomas in LS patients. We applied whole exome sequencing on nine adenomas (ten samples) and three assumed primary carcinomas (five samples) of an LS patient developing the tumors during a 21-year follow-up period. We compared the findings to the tumor profiles of two additional LS cases ascertained through colorectal tumor multiplicity, as well as to ten adenomas and 15 carcinomas from 23 unrelated LS patients with no elevated adenoma burden from the same population. As LS associated cancers can arise via several molecular pathways, we also profiled the tumors for CpG Island Methylator Phenotype (CIMP), and LINE-1 methylation. All tumors were microsatellite unstable (MSI), and MSI was present in several samples derived from normal mucosa as well. Interestingly, frequent frameshift variants in RNF43 were shared among substantial number of the tumors of our primary case and the tumors of LS cases with multiple tumors but almost absent in our control LS cases. The RNF43 variants were completely absent in the normal tissue, indicating tumor-associated mutational hotspots. The RNF43 status correlated with the mutational signature SBS96. Contrary to LS tumors from the reference set with no elevated colorectal tumor burden, the somatic variants occurred significantly more frequently at C>T in the CpG context, irrespective of CIMP or LINE-1 status, potentially indicating other, yet unknown methylation-related mechanisms. There were no signs of somatic mosaicism affecting the MMR genes. Somatic variants in APC and CTNNB1 were unique to each tumor. Frequent somatic RNF43 hot spot variants combined with SBS96 signature and increased tendency to DNA methylation may contribute to tumor multiplicity in LS.

High risk of multiple gastric cancers in Japanese individuals with Lynch syndrome.

Lynch syndrome (LS) is a dominantly inherited syndrome characterized by an increased risk for LS associated tumors such as colorectal cancer (CRC) and gastric cancer (GC). However, the clinical benefit of surveillance for GC remains unclear while it has already been recommended for CRC. This study aimed to elucidate the clinical features of GC in Japanese individuals with LS, and the risk of developing multiple GCs to build regional-tailored surveillance programs in LS patients with GC. Data on Japanese individuals with LS were retrospectively collected from a single institution. The clinical features of GC, including the cumulative risk of multiple GCs, were analyzed. Among 96 individuals with LS (MLH1/MSH2/MSH6, 75:20:1), 32 GC lesions were detected in 15 individuals with LS (male/female, 11:4). The median age at initial GC diagnosis was 52.7 y (range: 28-71). Histological examination revealed a predominance of intestinal type (19/24: 87.5%). Moreover, the majority of the GC lesions (82%) were determined to have high-frequency of microsatellite instability. The cumulative risk of individuals with LS developing GC at 70 y was 31.3% (MLH1 36.1%, MSH2 18.0%). Notably, the cumulative risk of individuals with LS developing metachronous and/or synchronous GCs at 0, 10 and 20 y after initial diagnosis of GC was 26.7%, 40.7%, and 59.4%, respectively. Due to a higher risk of developing multiple GCs, intensive surveillance might be especially recommended for Japanese individuals with LS associated initial GC.

Familial syndromes associated with testicular and paratesticular neoplasms: a comprehensive review.

A syndromic association between a subset of testicular/paratesticular neoplasms is well established. Such examples include Carney complex and large cell calcifying Sertoli cell tumor, Peutz-Jeghers syndrome and intratubular large cell hyalinizing Sertoli cell neoplasia, and VHL syndrome and clear cell papillary cystadenoma of the epididymis.However, recent studies proposed potential novel links between some testicular and paratesticular neoplasms with certain tumor syndromes. While more studies are still needed to solidify these associations, recent research suggests that a subset of Leydig cell tumors may arise in patients with hereditary leiomyomatosis and renal cell carcinoma syndrome or that some seminomas may occur in Lynch syndrome patients. Additionally, an association between testicular sex cord stromal tumors and paratesticular sarcomas with Familial adenomatous polyposis syndrome and DICER1 syndrome, respectively, has been proposed as well. This review provides a comprehensive overview of the intricate relationship between familial syndromes and associated testicular and paratesticular tumors, shedding light on their clinicopathological and molecular characteristics.