Lynch syndrome-associated epithelial ovarian cancer and its immunological profile.

Introduction: Lynch syndrome is a multi-tumor syndrome characterized by mismatch repair deficiency (MMR-d), microsatellite instability (MSI), and increased tumor-infiltrating lymphocytes (TILs) making these tumors candidates for treatment with immune checkpoint inhibitors. However, response may depend on tumor-induced immune evasion mechanisms, e.g.

Expanding the genotype-phenotype spectrum in hereditary colorectal cancer by gene panel testing.

Hereditary syndromes causing colorectal cancer include both polyposis and non-polyposis syndromes. Overlapping phenotypes between the syndromes have been recognized and this make targeted molecular testing for single genes less favorable, instead there is a gaining interest for multi-gene panel-based approaches detecting both SNVs, indels and CNVs in the same assay. We applied a panel including 19 CRC susceptibility genes to 91 individuals of six phenotypic subgroups.

Frequent mismatch-repair defects link prostate cancer to Lynch syndrome.

Background: A possible role for prostate cancer in Lynch syndrome has been debated based on observations of mismatch-repair defective tumors and reports of an increased risk of prostate cancer in mutation carriers. Potential inclusion of prostate cancer in the Lynch syndrome tumor spectrum is relevant for family classification, risk estimates and surveillance recommendations in mutation carriers.

Methods: We used the population-based Danish HNPCC-register to identify all prostate cancers that developed in mutation carriers and in their first-degree relatives from 288 Lynch syndrome families.

Functional implications of the p.Cys680Arg mutation in the MLH1 mismatch repair protein.

In clinical genetic diagnostics, it is difficult to predict whether genetic mutations that do not greatly alter the primary sequence of the encoded protein causing unknown functional effects on cognate proteins lead to development of disease. Here, we report the clinical identification of c.2038 T>C missense mutation in exon 18 of the human MLH1 gene and biochemically characterization of the p.

Heterogenous mismatch-repair status in colorectal cancer.

Background: Immunohistochemical staining for mismatch repair proteins is efficient and widely used to identify mismatch repair defective tumors. The tumors typically show uniform and widespread loss of MMR protein staining. We identified and characterized colorectal cancers with alternative, heterogenous mismatch repair protein staining in order to delineate expression patterns and underlying mechanisms.

Efficient and reproducible identification of mismatch repair deficient colon cancer: validation of the MMR index and comparison with other predictive models.

Background: The identification of mismatch-repair (MMR) defective colon cancer is clinically relevant for diagnostic, prognostic and potentially also for treatment predictive purposes. Preselection of tumors for MMR analysis can be obtained with predictive models, which need to demonstrate ease of application and favorable reproducibility.

Methods: We validated the MMR index for the identification of prognostically favorable MMR deficient colon cancers and compared performance to 5 other prediction models.

Gain of chromosomal region 20q and loss of 18 discriminates between Lynch syndrome and familial colorectal cancer.

Lynch syndrome and familial colorectal cancer type X, FCCTX, represent the two predominant colorectal cancer syndromes. Whereas Lynch syndrome is clinically and genetically well defined, the genetic cause of FCCTX is unknown and genomic differences between Lynch syndrome and FCCTX tumours are largely unknown. We applied array-based comparative genomic hybridisation to 23 colorectal cancers from FCCTX with comparison to 23 Lynch syndrome tumours and to 45 sporadic colorectal cancers.

Cancer risks and immunohistochemical profiles linked to the Danish MLH1 Lynch syndrome founder mutation.

Founder mutations with a large impact in distinct populations have been described in Lynch syndrome. In Denmark, the MLH1 c.1667+2_1667_+8TAAATCAdelinsATTT mutation accounts for 25 % of the MLH1 mutant families.

Prognostic value of proliferation in pleomorphic soft tissue sarcomas: a new look at an old measure.

Though proliferation has repeatedly shown a prognostic role in sarcomas, it has not reached clinical application. We performed a comprehensive evaluation of the prognostic role of 5 proliferation measures in a large series of soft tissue sarcomas of the extremities and the trunk wall. One hundred ninety-six primary soft tissue sarcomas of the extremities and the trunk wall were subjected to DNA flow cytometry for quantification of S-phase fraction and to immunohistochemical evaluation of Ki-67, Top2a, p21, and p27Kip1.

Ezrin expression in rectal cancer predicts time to development of local recurrence.

Purpose: Improved outcome after rectal cancer surgery requires identification of novel risk factors of tumour recurrence in order to personalise therapy, that is, enhanced selection of high-risk patients to additional radiochemotherapy or intensified follow-up. In several tumour types, including colorectal cancer, high expression of the membrane-cytoskeleton linker ezrin has been suggested to impair prognosis but has not yet reached clinical application. We evaluated the expression of ezrin in rectal cancer with a focus on the identification of a marker for local tumour recurrence.

Challenges in the identification of MSH6-associated colorectal cancer: rectal location, less typical histology, and a subset with retained mismatch repair function.

Identification of Lynch syndrome tumors is challenging. This relates particularly to MSH6-associated cases, which show reduced penetrance of colorectal cancer and a higher age at diagnosis. We recorded the clinical and morphologic features of 52 MSH6-associated colorectal cancers in comparison with MLH1/MSH2-mutant tumors and sporadic mismatch repair-deficient cancers.

Broad phenotypic spectrum in familial adenomatous polyposis; from early onset and severe phenotypes to late onset of attenuated polyposis with the first manifestation at age 72.

Background: Familial adenomatous polyposis (FAP) is typically characterized by multiple colonic polyps and frequent extracolonic features. Whereas the number of colonic polyps has been linked to the APC gene mutation, possible genotype-phenotype correlations largely remain to be defined for the extracolonic manifestations.

Methods: Full genomic sequencing combined with multiplex ligation-dependent probe amplification was used to identify APC gene mutations, which were correlated to the clinical presentations.

Detection and precise mapping of germline rearrangements in BRCA1, BRCA2, MSH2, and MLH1 using zoom-in array comparative genomic hybridization (aCGH).

Disease-predisposing germline mutations in cancer susceptibility genes may consist of large genomic rearrangements that are challenging to detect and characterize using standard PCR-based mutation screening methods. Here, we describe a custom-made zoom-in microarray comparative genomic hybridization (CGH) platform of 60mer oligonucleotides. The 4 x 44 K array format provides high-resolution coverage (200-300 bp) of 400-700 kb genomic regions surrounding six cancer susceptibility genes.

Multiplex polymerase chain reaction on FTA cards vs. flow cytometry for B-lymphocyte clonality.

Background: Two-colour flow cytometry was compared with multiplex PCR with capillary electrophoresis for clonality determination in specific categories of B-cell lymphoma. FTA cards were evaluated for preserving DNA from node imprints and expediting molecular analysis.

Methods: A single-tube multiplex PCR targeted IGH and lymphoma-specific translocations in DNA extracted from 180 frozen lymphoid tissues and DNA bound to FTA cards from 192 fresh tissues and 137 aspirates.

The added value of PMS2 immunostaining in the diagnosis of hereditary nonpolyposis colorectal cancer.

Identification and characterization of the genetic background in patients with the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome is important since control programmes can in a cost-effective manner prevent cancer development in high-risk individuals. HNPCC is caused by germline mismatch repair (MMR) gene mutations and the genetic analysis of HNPCC therefore includes assessment of microsatellite instability (MSI) and immunohistochemical MMR protein expression in the tumor tissue. MSI is found in >95% of the HNPCC-associated tumors and immunostaining using antibodies against the MMR proteins MLH1, MSH2, and MSH6 has been found to correctly pinpoint the affected gene in about 90% of the cases.

The contribution of the hereditary nonpolyposis colorectal cancer syndrome to the development of ovarian cancer.

Objective: Ovarian cancer has one of the highest fractions of hereditary cases. The hereditary breast and ovarian cancer syndrome, primarily due to mutations in BRCA1 and BRCA2, is the main cause of heredity, but also the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome confers an increased risk of ovarian cancer. In order to clarify the contribution of HNPCC to the development of ovarian cancer, we collected data on family history of cancer and characterized MMR function in a consecutive series of 128 tumors unselected for age at diagnosis and previously characterized for BRCA gene mutations.

Microsatellite instability analysis and/or immunostaining for the diagnosis of hereditary nonpolyposis colorectal cancer?

Hereditary nonpolyposis colorectal cancer (HNPCC) represents 2-4% of colorectal cancers and is caused by a constitutional defect in a mismatch repair (MMR) gene, most commonly affecting the genes MLH1, MSH2, and MSH6. The MMR defect results in an increased cancer risk with the greatest lifetime risks for colorectal cancer and endometrial cancer. The HNPCC-associated tumor phenotype is generally characterized by microsatellite instability (MSI) and immunohistochemical loss of expression of the affected MMR protein.

Microsatellite instability and expression of MLH1 and MSH2 in carcinomas of the small intestine.

Background: Carcinomas of the small intestine are rare, but the risk is greatly increased in patients with hereditary nonpolyposis colorectal cancer (HNPCC) due to an inherited mismatch repair (MMR) gene mutation, most commonly affecting the genes MLH1 or MSH2. Defective MMR is characterized by microsatellite instability (MSI) and loss of MMR protein expression in the tumor tissue. However, a subset of several sporadic tumor types, including about 15% of colon cancers, also evolve through defective MMR.

High frequency of microsatellite instability and loss of mismatch-repair protein expression in patients with double primary tumors of the endometrium and colorectum.

Background: Patients with the familial syndrome hereditary nonpolyposis colorectal carcinoma (HNPCC) exhibit an increased risk for several tumor types, of which the greatest lifetime risk is for colorectal and endometrial carcinoma. HNPCC is caused by a germline mutation in one of several identified mismatch repair (MMR) genes and typically presents with microsatellite instability (MSI) and frequent loss of MMR protein expression in the tumor tissue. The objective of this study was to estimate the proportion of double primary tumors of the endometrium and colorectum that displays tumor characteristics suggestive of MMR deficiency.