Dominantly inherited micro-satellite instable cancer - the four Lynch syndromes - an EHTG, PLSD position statement.

The recognition of dominantly inherited micro-satellite instable (MSI) cancers caused by pathogenic variants in one of the four mismatch repair (MMR) genes MSH2, MLH1, MSH6 and PMS2 has modified our understanding of carcinogenesis. Inherited loss of function variants in each of these MMR genes cause four dominantly inherited cancer syndromes with different penetrance and expressivities: the four Lynch syndromes. No person has an "average sex "or a pathogenic variant in an "average Lynch syndrome gene" and results that are not stratified by gene and sex will be valid for no one. Carcinogenesis may be a linear process from increased cellular division to localized cancer to metastasis. In addition, in the Lynch syndromes (LS) we now recognize a dynamic balance between two stochastic processes: MSI producing abnormal cells, and the host's adaptive immune system's ability to remove them. The latter may explain why colonoscopy surveillance does not reduce the incidence of colorectal cancer in LS, while it may improve the prognosis. Most early onset colon, endometrial and ovarian cancers in LS are now cured and most cancer related deaths are after subsequent cancers in other organs. Aspirin reduces the incidence of colorectal and other cancers in LS. Immunotherapy increases the host immune system's capability to destroy MSI cancers. Colonoscopy surveillance, aspirin prevention and immunotherapy represent major steps forward in personalized precision medicine to prevent and cure inherited MSI cancer.

Targeted molecular profiling of epithelial ovarian cancer from Italian BRCA wild-type patients with a BRCA and PARP pathways gene panel.

Ovarian cancer (OC) is the fifth most common type of cancer in women and the fourth most common cause of cancer death in women. Identification of pathogenic variants in OC tissues has an important clinical significance for therapeutic and prevention purposes. This study aims to evaluate the mutational profile of a patient cohort, negative for BRCA1/2 germinal variants and Mismatch Repair defects, using next-generation sequencing (NGS) approach on DNA from formalin-fixed paraffin-embedded samples. We used a custom NGS panel, targeting 34 cancer-related genes, mainly of the BRCA and PARP pathways, and analyzed NGS data to identify somatic and germline variants in Italian patients affected by primary epithelial ovarian cancer. We analyzed 75 epithelial ovarian cancer tissues and identified 54 pathogenic variants and 56 variants of unknown significance. TP53 was characterized by the highest mutational rate, occurring in 55% of tested epithelial ovarian cancers (EOCs). Interestingly, a subset of 8 EOCs showed pathogenic variants of homologous recombination pathway, which could be sensitive to PARP-inhibitor therapies. Germline analysis of actionable genes revealed 4 patients carrier of pathogenic germline variants respectively of RAD51C (2 patients), RAD51D, and PALB2. Molecular profiling of EOCs using our custom NGS panel has enabled the detection of both somatic and germline variants, allowing the selection of patients suitable for targeted therapies, and the identification of high-risk OC families that can benefit from genetic counseling and testing.

Colorectal cancer incidences in Lynch syndrome: a comparison of results from the prospective lynch syndrome database and the international mismatch repair consortium.

OBJECTIVE: To compare colorectal cancer (CRC) incidences in carriers of pathogenic variants of the MMR genes in the PLSD and IMRC cohorts, of which only the former included mandatory colonoscopy surveillance for all participants. METHODS: CRC incidences were calculated in an intervention group comprising a cohort of confirmed carriers of pathogenic or likely pathogenic variants in mismatch repair genes (path_MMR) followed prospectively by the Prospective Lynch Syndrome Database (PLSD). All had colonoscopy surveillance, with polypectomy when polyps were identified. Comparison was made with a retrospective cohort reported by the International Mismatch Repair Consortium (IMRC). This comprised confirmed and inferred path_MMR carriers who were first- or second-degree relatives of Lynch syndrome probands. RESULTS: In the PLSD, 8,153 subjects had follow-up colonoscopy surveillance for a total of 67,604 years and 578 carriers had CRC diagnosed. Average cumulative incidences of CRC in path_MLH1 carriers at 70 years of age were 52% in males and 41% in females; for path_MSH2 50% and 39%; for path_MSH6 13% and 17% and for path_PMS2 11% and 8%. In contrast, in the IMRC cohort, corresponding cumulative incidences were 40% and 27%; 34% and 23%; 16% and 8% and 7% and 6%. Comparing just the European carriers in the two series gave similar findings. Numbers in the PLSD series did not allow comparisons of carriers from other continents separately. Cumulative incidences at 25 years were < 1% in all retrospective groups. CONCLUSIONS: Prospectively observed CRC incidences (PLSD) in path_MLH1 and path_MSH2 carriers undergoing colonoscopy surveillance and polypectomy were higher than in the retrospective (IMRC) series, and were not reduced in path_MSH6 carriers. These findings were the opposite to those expected. CRC point incidence before 50 years of age was reduced in path_PMS2 carriers subjected to colonoscopy, but not significantly so.

Risk-reducing hysterectomy and bilateral salpingo-oophorectomy in female heterozygotes of pathogenic mismatch repair variants: a Prospective Lynch Syndrome Database report.

PURPOSE: To determine impact of risk-reducing hysterectomy and bilateral salpingo-oophorectomy (BSO) on gynecological cancer incidence and death in heterozygotes of pathogenic MMR (path_MMR) variants. METHODS: The Prospective Lynch Syndrome Database was used to investigate the effects of gynecological risk-reducing surgery (RRS) at different ages. RESULTS: Risk-reducing hysterectomy at 25 years of age prevents endometrial cancer before 50 years in 15%, 18%, 13%, and 0% of path_MLH1, path_MSH2, path_MSH6, and path_PMS2 heterozygotes and death in 2%, 2%, 1%, and 0%, respectively. Risk-reducing BSO at 25 years of age prevents ovarian cancer before 50 years in 6%, 11%, 2%, and 0% and death in 1%, 2%, 0%, and 0%, respectively. Risk-reducing hysterectomy at 40 years prevents endometrial cancer by 50 years in 13%, 16%, 11%, and 0% and death in 1%, 2%, 1%, and 0%, respectively. BSO at 40 years prevents ovarian cancer before 50 years in 4%, 8%, 0%, and 0%, and death in 1%, 1%, 0%, and 0%, respectively. CONCLUSION: Little benefit is gained by performing RRS before 40 years of age and premenopausal BSO in path_MSH6 and path_PMS2 heterozygotes has no measurable benefit for mortality. These findings may aid decision making for women with LS who are considering RRS.

Detection of Germline Variants in 450 Breast/Ovarian Cancer Families with a Multi-Gene Panel Including Coding and Regulatory Regions.

With the progress of sequencing technologies, an ever-increasing number of variants of unknown functional and clinical significance (VUS) have been identified in both coding and non-coding regions of the main Breast Cancer (BC) predisposition genes. The aim of this study is to identify a mutational profile of coding and intron-exon junction regions of 12 moderate penetrance genes (ATM, BRIP1, CDH1, CHEK2, NBN, PALB2, PTEN, RAD50, RAD51C, RAD51D, STK11, TP53) in a cohort of 450 Italian patients with Hereditary Breast/Ovarian Cancer Syndrome, wild type for germline mutation in BRCA1/2 genes. The analysis was extended to 5'UTR and 3'UTR of all the genes listed above and to the BRCA1 and BRCA2 known regulatory regions in a subset of 120 patients. The screening was performed through NGS target resequencing on the Illumina platform MiSeq. 8.7% of the patients analyzed is carriers of class 5/4 coding variants in the ATM (3.6%), BRIP1 (1.6%), CHEK2 (1.8%), PALB2 (0.7%), RAD51C (0.4%), RAD51D (0.4%), and TP53 (0.2%) genes, while variants of uncertain pathological significance (VUSs)/class 3 were identified in 9.1% of the samples. In intron-exon junctions and in regulatory regions, variants were detected respectively in 5.1% and in 32.5% of the cases analyzed. The average age of disease onset of 44.4 in non-coding variant carriers is absolutely similar to the average age of disease onset in coding variant carriers for each proband's group with the same cancer type. Furthermore, there is not a statistically significant difference in the proportion of cases with a tumor onset under age of 40 between the two groups, but the presence of multiple non-coding variants in the same patient may affect the aggressiveness of the tumor and it is worth underlining that 25% of patients with an aggressive tumor are carriers of a PTEN 3'UTR-variant. This data provides initial information on how important it might be to extend mutational screening to the regulatory regions in clinical practice.

Correction: Cancer risks by gene, age, and gender in 6350 carriers of pathogenic mismatch repair variants: findings from the Prospective Lynch Syndrome Database.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Cancer risks by gene, age, and gender in 6350 carriers of pathogenic mismatch repair variants: findings from the Prospective Lynch Syndrome Database.

PURPOSE: Pathogenic variants affecting MLH1, MSH2, MSH6, and PMS2 cause Lynch syndrome and result in different but imprecisely known cancer risks. This study aimed to provide age and organ-specific cancer risks according to gene and gender and to determine survival after cancer. METHODS: We conducted an international, multicenter prospective observational study using independent test and validation cohorts of carriers of class 4 or class 5 variants. After validation the cohorts were merged providing 6350 participants and 51,646 follow-up years. RESULTS: There were 1808 prospectively observed cancers. Pathogenic MLH1 and MSH2 variants caused high penetrance dominant cancer syndromes sharing similar colorectal, endometrial, and ovarian cancer risks, but older MSH2 carriers had higher risk of cancers of the upper urinary tract, upper gastrointestinal tract, brain, and particularly prostate. Pathogenic MSH6 variants caused a sex-limited trait with high endometrial cancer risk but only modestly increased colorectal cancer risk in both genders. We did not demonstrate a significantly increased cancer risk in carriers of pathogenic PMS2 variants. Ten-year crude survival was over 80% following colon, endometrial, or ovarian cancer. CONCLUSION: Management guidelines for Lynch syndrome may require revision in light of these different gene and gender-specific risks and the good prognosis for the most commonly associated cancers.

Lynch syndrome-related non-endometrioid endometrial cancer: analysis of outcomes.

OBJECTIVE: Women with Lynch syndrome have a risk up to 40-60% of developing endometrial cancer, which is higher than their risk of developing colorectal or ovarian cancer. To date, no data on the outcomes of patients with Lynch syndrome diagnosed with non-endometrioid endometrial cancer are available. The goal of this study was to evaluate the outcome of patients with Lynch syndrome diagnosed with non-endometrioid endometrial cancer. METHODS: Data from consecutive patients diagnosed with Lynch syndrome and with a histological diagnosis of non-endometrioid endometrial cancer were retrospectively collected in two referral institutes in Italy. A case-control comparison (applying a propensity matching algorithm) was performed in order to compare patients with proven Lynch syndrome and controls. Inclusion criteria were: (a) histologically-proven endometrial cancer; (b) detection of a germline pathogenic variant in one of the MMR genes; (c) adequate follow-up. Only carriers of pathogenic or likely pathogenic variants (ie, class 5 and 4 according to the InSiGHT classification) were included in the study. Survival outcomes were assessed using KaplanMeier and Cox models. RESULTS: Overall, 137 patients with Lynch syndrome were collected. Mean patient age was 49.2 (10.9) years. Genes involved in the Lynch syndrome included MLH1, MSH2, and MSH6 in 43%, 39%, and 18% of cases, respectively. The study population included 27 patients with non-endometrioid endometrial cancer, who were matched 1:2 with patients with sporadic cancers using a propensity matching algorithm. After a median follow-up of 134 months (range 1-295), 2 (7.4%) of the 27 patients developed recurrent disease (3 and 36 months) and subsequently died of disease (7 and 91 months). Patients diagnosed with Lynch syndrome experienced better disease-free survival (HR 7.86 (95% CI 1.79 to 34.5); p=0.006) and overall survival (HR 5.33 (95% CI 1.18 to 23.9); p=0.029) than controls. CONCLUSIONS: Non-endometrioid endometrial cancer occurring in patients with Lynch syndrome might be associated with improved oncologic outcomes compared with controls. Genetic/molecular profiling should be investigated in order to better understand the mechanism underlying the prognosis.

STELO: a new tool for family physicians for the correct identification of inherited cancer syndromes.

BACKGROUND: The hereditary cancer syndromes represent overall <10% of all cancers. These syndromes are not irrelevant for public health because all the cancers typical of these syndromes affected young people and many members of the same family and the cancers are more aggressive than the sporadic ones and need specific surgery and medical therapy. We developed a new family assessment tool: STELO designed for family physicians to identify patients could benefit from Cancer Genetic Counselling. OBJECTIVE: Test the sensitivity and specificity of a new assessment tool for the correct identification of inherited cancer syndromes. METHODS: Retrospectively we tested the new tool on a subset of patients who had already undergone genetic counselling at the Cancer Genetic Counselling Service of ASST (Azienda Socio Sanitaria Territoriale) Settelaghi Varese, to investigate sensitivity, specificity and applicability of this new tool in routine genetic screening. STELO responses were matched against the opinion of two cancer geneticists (i.e. gold standard) who blinded each other decided if the history of these patients was properly suspected as a hereditary cancer syndrome. RESULTS: The Genetic Counselling Service followed 546 subjects from 2014 to 2015. STELO tool was tested retrospectively on these clinical records and resulted positive in 418 cases, out of 546 (76.5%). STELO reported, towards the gold standard, 88.5% and 52.3% of sensitivity and specificity, respectively. CONCLUSIONS: STELO has demonstrated to have a good sensitivity. The specificity was expectedly low given that STELO has been developed for general medicine, so it needs to be simple, practical, of rapid consultation and effectively used in clinical practice.

BRCA Methylation Testing Identifies a Subset of Ovarian Carcinomas without Germline Variants That Can Benefit from PARP Inhibitor.

Homologous Recombination Deficiency (HRD) is a frequent feature of high-grade epithelial ovarian carcinoma (EOC), associated with sensitivity to PARP-inhibitors (PARPi). The best characterized causes of HRD in EOCs are germline or somatic mutations in BRCA1 and BRCA2 genes. Although promoter methylation is a well-known mechanism of gene transcriptional repression, few data have been published about BRCA gene methylation in EOCs. In this retrospective study, we quantitatively analyzed by pyrosequencing a selected series of 90 formalin-fixed (FFPE) primary EOCs without BRCA germline mutations. We identified 20/88 (22.7%) EOCs showing BRCA promoter methylation, including 17/88 (19.3%) in BRCA1 and 4/86 (4.6%) in BRCA2 promoters, one of which showing concomitant BRCA1 methylation. Mean methylation levels were 49.6% and 45.8% for BRCA1 and BRCA2, respectively, with methylation levels ≥50% in 10/20 methylated EOCs. Constitutive BRCA methylation was excluded by testing blood-derived DNA. In conclusion, pyrosequencing methylation analysis of BRCA genes is a robust, quantitative and sensitive assay applicable to FFPE samples. Remarkably, a considerable subset of germline BRCA-negative EOCs showed somatic methylation and, likely, HRD. A subpopulation of women with BRCA methylation, even without BRCA mutations, could potentially benefit from PARP-inhibitors; further clinical studies are needed to clarify the predictive role of somatic BRCA methylation of PARP-therapy response.

Insight into genetic susceptibility to male breast cancer by multigene panel testing: Results from a multicenter study in Italy.

Breast cancer (BC) in men is rare and genetic predisposition is likely to play a relevant role in its etiology. Inherited mutations in BRCA1/2 account for about 13% of all cases and additional genes that may contribute to the missing heritability need to be investigated. In our study, a well-characterized series of 523 male BC (MBC) patients from the Italian multicenter study on MBC, enriched for non-BRCA1/2 MBC cases, was screened by a multigene custom panel of 50 cancer-associated genes. The main clinical-pathologic characteristics of MBC in pathogenic variant carriers and non-carriers were also compared. BRCA1/2 pathogenic variants were detected in twenty patients, thus, a total of 503 non-BRCA1/2 MBC patients were examined in our study. Twenty-seven of the non-BRCA1/2 MBC patients were carriers of germline pathogenic variants in other genes, including two APC p.Ile1307Lys variant carriers and one MUTYH biallelic variant carrier. PALB2 was the most frequently altered gene (1.2%) and PALB2 pathogenic variants were significantly associated with high risk of MBC. Non-BRCA1/2 pathogenic variant carriers were more likely to have personal (p = 0.0005) and family (p = 0.007) history of cancer. Results of our study support a central role of PALB2 in MBC susceptibility and show a low impact of CHEK2 on MBC predisposition in the Italian population. Overall, our data indicate that a multigene testing approach may benefit from appropriately selected patients with implications for clinical management and counseling of MBC patients and their family members.

Whole-exome sequencing and targeted gene sequencing provide insights into the role of PALB2 as a male breast cancer susceptibility gene.

BACKGROUND: Male breast cancer (MBC) is a rare disease whose etiology appears to be largely associated with genetic factors. BRCA1 and BRCA2 mutations account for about 10% of all MBC cases. Thus, a fraction of MBC cases are expected to be due to genetic factors not yet identified. To further explain the genetic susceptibility for MBC, whole-exome sequencing (WES) and targeted gene sequencing were applied to high-risk, BRCA1/2 mutation-negative MBC cases. METHODS: Germ-line DNA of 1 male and 2 female BRCA1/2 mutation-negative breast cancer (BC) cases from a pedigree showing a first-degree family history of MBC was analyzed with WES. Targeted gene sequencing for the validation of WES results was performed for 48 high-risk, BRCA1/2 mutation-negative MBC cases from an Italian multicenter study of MBC. A case-control series of 433 BRCA1/2 mutation-negative MBC and female breast cancer (FBC) cases and 849 male and female controls was included in the study. RESULTS: WES in the family identified the partner and localizer of BRCA2 (PALB2) c.419delA truncating mutation carried by the proband, her father, and her paternal uncle (all affected with BC) and the N-acetyltransferase 1 (NAT1) c.97C>T nonsense mutation carried by the proband's maternal aunt. Targeted PALB2 sequencing detected the c.1984A>T nonsense mutation in 1 of the 48 BRCA1/2 mutation-negative MBC cases. NAT1 c.97C>T was not found in the case-control series. CONCLUSIONS: These results add strength to the evidence showing that PALB2 is involved in BC risk for both sexes and indicate that consideration should be given to clinical testing of PALB2 for BRCA1/2 mutation-negative families with multiple MBC and FBC cases. Cancer 2017;123:210-218. © 2016 American Cancer Society.

Oxidative DNA damage induces hypomethylation in a compromised base excision repair colorectal tumourigenesis.

BACKGROUND: A compromised base excision repair (BER) promotes carcinogenesis by accumulating oxidative DNA-damaged products as observed in MUTYH-associated polyposis, a hereditary colorectal cancer syndrome marked by adenomas and cancers with an accumulation of 8-oxoguanine. Remarkably, DNA global demethylation has been shown to be mediated by BER, suggesting a relevant interplay with early colorectal tumourigenesis. To check this hypothesis, we investigated a cohort of 49 adenomas and 10 carcinomas, derived from 17 MUTYH-associated polyposis patients; as adenoma controls, we used a set of 36 familial adenomatous polyposis and 24 sporadic polyps. METHODS: Samples were analysed for their mutational and epigenetic status, measured as global LINE-1 (long interspersed nuclear element) and gene-specific LINE-1 MET methylation by mass spectrometry and pyrosequencing. RESULTS: MUTYH-associated polyposis adenomas were strikingly more hypomethylated than familial adenomatous and sporadic polyps for both DNA demethylation markers (P=0.032 and P=0.007 for LINE-1; P=0.004 and P<0.0001 for LINE-1 MET, respectively) with levels comparable to those of the carcinomas derived from the same patients. They also had mutations due mainly to KRAS/NRAS p.G12C, which was absent in the controls (P<0.0001 for both sets). CONCLUSIONS: Our results show that DNA demethylation, together with specific KRAS/NRAS mutations, drives the early steps of oxidative damage colorectal tumourigenesis.

Two Cases of Carcinosarcomas of the Ovary Involved in Hereditary Cancer Syndromes.

Ovarian carcinosarcomas (OCS), also known as malignant mixed mesodermal/Müllerian tumors, are rare neoplasms (1%-4% of all malignant ovarian tumors) composed of high-grade malignant epithelial and mesenchymal elements. OCS occurs in older women. It is associated with a poor outcome and is usually not involved in inherited cancer syndromes. We present 2 cases of OCS; one arising in a patient with a pathogenetic BRCA1 mutation and the other in a woman affected by Lynch Syndrome (LS) carrying a MSH6 germline mutation. To the best of our knowledge, this is the first time that this second type of case has been reported. In this study, we investigated somatic impairment of the wild-type BRCA1 and MSH6 alleles in the OCS of these 2 patients. We also explored in both OCS, the occurrence of TP53 loss of function, which is a genetic alteration known to occur in BRCA-linked ovarian tumorigenesis but not in LS tumors. Moreover, we also provide further data about the histogenesis of OCS.

Somatic Testing on Gynecological Cancers Improve the Identification of Lynch Syndrome.

OBJECTIVE: Recent data from the literature indicate gynecological cancers (GCs) as sentinel cancers for a diagnosis of Lynch syndrome (LS). Clinical approaches to identifying LS have low sensitivity, whereas somatic tests on GCs may be a more sensitive and cost-effective strategy. METHODS: A series of 78 GCs belonging to 74 patients sent to the Genetic Counselling Service were investigated using microsatellite instability, immunohistochemical expression of mismatch repair (MMR) genes, and MLH1 promoter methylation. RESULTS: The presence of microsatellite instability was observed in 67.5% of GCs, and the absence of immunohistochemical expression of at least 1 of the 4 MMR proteins was observed in 71.4% of GCs, showing 96.1% concordance between the methods. Methylation analysis using methylation specific multiplex ligation-dependent probe amplification performed on 35 samples revealed MLH1 promoter hypermethylation in 18 cases (54%). Molecular analysis identified 36 LS carriers of MMR variants (27 pathogenetic and 9 variants of uncertain significance), and, interestingly, 3 LS patients had MLH1 methylated GC.With regard to histological features, LS-related GCs included endocervical cancers and also histological types different from the endometrioid cancers. The presence of peritumoral lymphocytes in GCs was statistically associated with LS tumors. CONCLUSIONS: Somatic analysis is a useful strategy to distinguish sporadic from LS GC. Our data allow the identification of a subset of LS patients otherwise unrecognized on the basis of clinical or family history alone. In addition, our results indicate that some clinicopathological features including age of GC diagnosis; presence of peritumoral lymphocytes; isthmic, endocervical sites, and body mass index value could be useful criteria to select patients for genetic counseling.

Multiple primary melanomas (MPMs) and criteria for genetic assessment: MultiMEL, a multicenter study of the Italian Melanoma Intergroup.

BACKGROUND: Multiple primary melanoma (MPM), in concert with a positive family history, is a predictor of cyclin-dependent kinase (CDK) inhibitor 2A (CDKN2A) germline mutations. A rule regarding the presence of either 2 or 3 or more cancer events (melanoma and pancreatic cancer) in low or high melanoma incidence populations, respectively, has been established to select patients for genetic referral. OBJECTIVE: We sought to determine the CDKN2A/CDK4/microphthalmia-associated transcription factor mutation rate among Italian patients with MPM to appropriately direct genetic counseling regardless of family history. METHODS: In all, 587 patients with MPM and an equal number with single primary melanomas and control subjects were consecutively enrolled at the participating centers and tested for CDKN2A, CDK4, and microphthalmia-associated transcription factor. RESULTS: CDKN2A germline mutations were found in 19% of patients with MPM versus 4.4% of patients with single primary melanoma. In familial MPM cases the mutation rate varied from 36.6% to 58.8%, whereas in sporadic MPM cases it varied from 8.2% to 17.6% in patients with 2 and 3 or more melanomas, respectively. The microphthalmia-associated transcription factor E318K mutation accounted for 3% of MPM cases altogether. LIMITATIONS: The study was hospital based, not population based. Rare novel susceptibility genes were not tested. CONCLUSION: Italian patients who developed 2 melanomas, even in situ, should be referred for genetic counseling even in the absence of family history.

Concomitant mutation and epimutation of the MLH1 gene in a Lynch syndrome family.

Lynch syndrome (LS) is an inherited predisposition cancer syndrome, typically caused by germline mutations in the mismatch repair genes MLH1, MSH2, MSH6 and PMS2. In the last years, a role for epimutations of the same genes has also been reported. MLH1 promoter methylation is a well known mechanism of somatic inactivation in tumors, and more recently, several cases of constitutional methylation have been identified. In four subjects affected by multiple tumors and belonging to a suspected LS family, we detected a novel secondary MLH1 gene epimutation. The methylation of MLH1 promoter was always linked in cis with a 997 bp-deletion (c.-168_c.116+713del), that removed exon 1 and partially involved the promoter of the same gene. Differently from cases with constitutional primary MLH1 inactivation, this secondary methylation was allele-specific and CpGs of the residual promoter region were totally methylated, leading to complete allele silencing. In the colon tumor of the proband, MLH1 and PMS2 expression was completely lost as a consequence of a pathogenic somatic point mutation (MLH1 c.199G>A, p.Gly67Arg) that also abrogated local methylation by destroying a CpG site. The evidences obtained highlight how MLH1 mutations and epimutations can reciprocally influence each other and suggest that an altered structure of the MLH1 locus results in epigenetic alteration.

Deregulation of ETS1 and FLI1 contributes to the pathogenesis of diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common form of human lymphoma. DLBCL is a heterogeneous disease characterized by different genetic lesions. We herein report the functional characterization of a recurrent gain mapping on chromosome 11q24.3, found in 23% of 166 DLBCL cases analyzed. The transcription factors ETS1 and FLI1, located within the 11q24.3 region, had significantly higher expression in clinical samples carrying the gain. Functional studies on cell lines showed that ETS1 and FLI1 cooperate in sustaining DLBCL proliferation and viability and regulate genes involved in germinal center differentiation. Taken together, these data identify the 11q24.3 gain as a recurrent lesion in DLBCL leading to ETS1 and FLI1 deregulated expression, which can contribute to the pathogenesis of this disease.

Immunohistochemical and molecular pattern of p53 in epithelial ovarian cancers negative for germline BRCA1/2 variants.

Epithelial ovarian cancers (EOC) associated with germline or somatic BRCA pathogenetic variants have a significantly higher rate of TP53aberrations. The majority of TP53 mutations are detectable by immunohistochemistry and several studies demonstrated that an abnormal p53 pattern characterized high-grade EOCs. An abnormal p53 immunohistochemical staining in fallopian tube (serous tubal intraepithelial carcinoma (STIC) and "p53 signature" is considered as a precancerous lesion of high-grade EOCs and it is often found in fallopian tube tissues of BRCA germline mutated patients suggesting that STIC is an early lesion and the TP53 mutation is an early driver event of BRCA mutated high-grade EOCs. No relevant data are present in literature about the involvement of p53 abnormal pattern in EOC carcinogenesis of patients negative for germline BRCA variants. We describe TP53 mutation results in relationship to the immunohistochemical pattern of p53 expression in a series of EOCs negative for BRCA1 and BRCA2 germline mutations. In addition, we also investigated STIC presence and "p53 signature" in fallopian tube sampling of these EOCs. Our results demonstrate that TP53 alterations are frequent and early events in sporadic EOCs including also low-grade carcinomas. Also in this series, STIC is associated with an abnormal p53 pattern in fallopian tubes of high-grade EOCs. In summary, TP53 aberrations are the most frequent and early molecular events in EOC carcinogenesis independently from BRCA mutation status.