Testing for Lynch Syndrome in Endometrial Carcinoma: From Universal to Age-Selective MLH1 Methylation Analysis.

International guidelines recommend universal screening of endometrial carcinoma (EC) patients for Lynch syndrome (LS). This screening is generally based on mismatch repair (MMR) protein immunohistochemistry followed by MLH1 methylation analysis of MLH1-negative cases to exclude the likely sporadic cases from germline testing. As LS-associated EC is uncommon in the elderly, age-selective methylation testing could improve cost-efficiency. We performed MMR immunohistochemistry on 821 unselected ECs (clinic-based cohort) followed by a MLH1 promoter methylation test of all MLH1/PMS2-negative tumors. Non-methylated MLH1-deficient cases underwent NGS and MLPA-based germline analyses to identify MLH1 mutation carriers. A reduction in the test burden and corresponding false negative rates for LS screening were investigated for various age cut-offs. In addition, the age distribution of 132 MLH1 mutation carriers diagnosed with EC (registry-based cohort) was examined. A germline MLH1 mutation was found in 2/14 patients with non-methylated MLH1-deficient EC. When compared to a universal methylation analysis, selective testing with a cut-off age of 65 years, would have reduced the testing effort by 70.7% with a false negative rate for LS detection of 0% and 3% in the clinic and registry-based cohorts, respectively. The use of age-selective methylation analysis is a feasible way of reducing the costs and laboratory burden in LS screening for EC patients.

The variant rs77559646 associated with aggressive prostate cancer disrupts ANO7 mRNA splicing and protein expression.

Prostate cancer is among the most common cancers in men, with a large fraction of the individual risk attributable to heritable factors. A majority of the diagnosed cases does not lead to a lethal disease, and hence biological markers that can distinguish between indolent and fatal forms of the disease are of great importance for guiding treatment decisions. Although over 300 genetic variants are known to be associated with prostate cancer risk, few have been associated with the risk of an aggressive disease. One such variant is rs77559646 located in ANO7. This variant has a dual function. It constitutes a missense mutation in the short isoform of ANO7 and a splice region mutation in full-length ANO7. In this study, we have analyzed the impact of the variant allele of rs77559646 on ANO7 mRNA splicing using a minigene splicing assay and by performing splicing analysis with the tools IRFinder (intron retention finder), rMATS (replicate multivariate analysis of transcript splicing) and LeafCutter on RNA sequencing data from prostate tissue of six rs77559646 variant allele carriers and 43 non-carriers. The results revealed a severe disruption of ANO7 mRNA splicing in rs77559646 variant allele carriers. Immunohistochemical analysis of prostate samples from patients homozygous for the rs77559646 variant allele demonstrated a loss of apically localized ANO7 protein. Our study is the first to provide a mechanistic explanation for the impact of a prostate cancer risk SNP on ANO7 protein production. Furthermore, the rs77559646 variant is the first known germline loss-of-function mutation described for ANO7. We suggest that loss of ANO7 contributes to prostate cancer progression.

The interactome of the prostate-specific protein Anoctamin 7.

BACKGROUND: Elevated Anoctamin 7 (ANO7) expression is associated with poor survival in prostate cancer patients. OBJECTIVE: The aim was to discover proteins that interact with ANO7 to understand its functions and regulatory mechanisms. METHODS: The proximity-dependent biotin identification (BioID) method was utilized. ANO7 fused to biotin ligase was transiently transfected into LNCaP cells, and the biotinylated proteins were collected and analysed by mass spectrometry. Four identified proteins were stained with dual fluorescent immunostaining and visualized using Stimulated emission depletion microscopy (STED). RESULTS: After bioinformatic filtering steps, 64 potentially ANO7-interacting proteins were identified and analysed with the GO enrichment analysis tool. One of the most prominently enriched cellular components was cellular vesicle. Co-localization was showed for staphylococcal nuclease and tudor domain containing 1 (SND1), heat shock protein family A (Hsp70) member 1A (HSPA1A), adaptor related protein complex 2 subunit beta 1 (AP2B1) and coatomer protein complex subunit gamma 2 (COPG2). CONCLUSIONS: This is the first study in which ANO7 interacting proteins have been identified. Although further studies are needed, the findings reported here expand our understanding of the role and regulation of ANO7 in prostate cancer cells. Furthermore, these results are likely to introduce new targets for the novel cancer therapies.

ANO7 rs77559646 Is Associated With First-line Docetaxel Treatment Response in Metastatic Castration-resistant Prostate Cancer.

BACKGROUND: Identification of genetic prognostic biomarkers, such as germline variants, are urgently needed to choose optimal treatment for metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: The prognostic value of anoctamin 7 (ANO7) rs77559646 on docetaxel response was tested in a prospective PROSTY randomized trial and a retrospective Auria Biobank set. The variant rs77559646 was genotyped and its association with progression-free survival (PFS) and overall survival (OS) was tested. RESULTS: In comparison with the non-carriers, the variant carriers had longer PFS (p=0.005) and OS (p=0.003) in the PROSTY cohort. In the retrospective cohort, there was a borderline association with PFS (p=0.09), but not in OS (p=0.9). In both cohorts, Cox regression multivariate models revealed that rs77559646 was an independent prognostic factor for favourable PFS. CONCLUSION: The rs77559646 was shown to be a prognostic germline biomarker for better response to docetaxel treatments. To our knowledge, this is the first time that a non-coding germline variant has been associated with chemotherapy of mCRPC.

ANO7 is associated with aggressive prostate cancer.

Prostate cancer is one of the most common and heritable human cancers. Our aim was to find germline biomarkers that can predict disease outcome. We previously detected predisposing signals at 2q37, the location of the prostate specific ANO7 gene. To investigate, in detail, the associations between the ANO7 gene and PrCa risk and disease aggressiveness, ANO7 was sequenced in castration resistant tumors together with samples from unselected PrCa patients and unaffected males. Two pathogenic variants were discovered and genotyped in 1769 patients and 1711 unaffected males. Expression of ANO7 vs. PrCa aggressiveness was investigated. Different databases along with Swedish and Norwegian cohorts were used for validation. Case-control and aggressive vs. nonaggressive association analyses were performed against risk and/or cancer aggressiveness. The ANO7 mRNA level and patient survival were analyzed using expression data from databases. Variant rs77559646 showed both risk (OR 1.40; p = 0.009, 95% CI 1.09-1.78) and association with aggressive PrCa (Genotype test p = 0.04). It was found to be an eQTL for ANO7 (Linear model p-values for Finnish patients p = 0.009; Camcap prostate tumor p = 2.53E-06; Stockholm prostate tumor cohort p = 1.53E-13). rs148609049 was not associated with risk, but was related to shorter survival (HR 1.56; 95% CI 1.03-2.36). High ANO7 expression was independently linked to poor survival (HR 18.4; 95% CI 1.43-237). ANO7 genotypes correlate with expression and biochemical relapse, suggesting that ANO7 is a potential PrCa susceptibility gene and that its elevated expression correlates with disease severity and outcome.

Genome-wide association of familial prostate cancer cases identifies evidence for a rare segregating haplotype at 8q24.21.

Previous genome-wide association studies (GWAS) of prostate cancer risk focused on cases unselected for family history and have reported over 100 significant associations. The International Consortium for Prostate Cancer Genetics (ICPCG) has now performed a GWAS of 2511 (unrelated) familial prostate cancer cases and 1382 unaffected controls from 12 member sites. All samples were genotyped on the Illumina 5M+exome single nucleotide polymorphism (SNP) platform. The GWAS identified a significant evidence for association for SNPs in six regions previously associated with prostate cancer in population-based cohorts, including 3q26.2, 6q25.3, 8q24.21, 10q11.23, 11q13.3, and 17q12. Of note, SNP rs138042437 (p = 1.7e(-8)) at 8q24.21 achieved a large estimated effect size in this cohort (odds ratio = 13.3). 116 previously sampled affected relatives of 62 risk-allele carriers from the GWAS cohort were genotyped for this SNP, identifying 78 additional affected carriers in 62 pedigrees. A test for an excess number of affected carriers among relatives exhibited strong evidence for co-segregation of the variant with disease (p = 8.5e(-11)). The majority (92 %) of risk-allele carriers at rs138042437 had a consistent estimated haplotype spanning approximately 100 kb of 8q24.21 that contained the minor alleles of three rare SNPs (dosage minor allele frequencies <1.7 %), rs183373024 (PRNCR1), previously associated SNP rs188140481, and rs138042437 (CASC19). Strong evidence for co-segregation of a SNP on the haplotype further characterizes the haplotype as a prostate cancer predisposition locus.