Differential expression of PTEN gene correlates with phenotypic heterogeneity in three cases of patients showing clinical manifestations of PTEN hamartoma tumour syndrome

The Epithelial to Mesenchymal Transition in Colorectal Cancer Progression: The Emerging Role of Succinate Dehydrogenase Alterations and Succinate Accumulation

Colorectal cancer (CRC) stands as the third most significant contributor to cancer-related mortality worldwide. A major underlying reason is that the detection of CRC usually occurs at an advanced metastatic stage, rendering therapies ineffective. In the progression from the in situ neoplasia stage to the advanced metastatic stage, a critical molecular mechanism involved is the epithelial-to-mesenchymal transition (EMT). This intricate transformation consists of a series of molecular changes, ultimately leading the epithelial cell to relinquish its features and acquire mesenchymal and stem-like cell characteristics. The EMT regulation involves several factors, such as transcription factors, cytokines, micro RNAs and long noncoding RNAs. Nevertheless, recent studies have illuminated an emerging link between metabolic alterations and EMT in various types of cancers, including colorectal cancers. In this review, we delved into the pivotal role played by EMT during CRC progression, with a focus on highlighting the relationship between the alterations of the tricarboxylic acid cycle, specifically those involving the succinate dehydrogenase enzyme, and the activation of the EMT program. In fact, emerging evidence supports the idea that elucidating the metabolic modifications that can either induce or inhibit tumor progression could be of immense significance for shaping new therapeutic approaches and preventative measures. We conclude that an extensive effort must be directed towards research for the standardization of drugs that specifically target proteins such as SDH and SUCNR1, but also TRAP1, PDH, ERK1/2, STAT3 and the HIF1-α catabolism.

Genetic heterogeneity of disorders with overgrowth and intellectual disability: Experience from a center in North India

Overgrowth, defined as height and/or OFC ≥ +2SD, characterizes a subset of patients with syndromic intellectual disability (ID). Many of the disorders with overgrowth and ID (OGID) are rare and the full phenotypic and genotypic spectra have not been unraveled. This study was undertaken to characterize the phenotypic and genotypic profile of patients with OGID. Patients with OGID were ascertained from the cohort of patients who underwent cytogenetic microarray (CMA) and/or exome sequencing (ES) at our center over a period of 6 years. Thirty-one subjects (six females) formed the study group with ages between 3.5 months and 13 years. CMA identified pathogenic deletions in two patients. In another 11 patients, a disease causing variant was detected by ES. The spectrum of disorders encompassed aberrations in genes involved in the two main pathways associated with OGID. These were genes involved in epigenetic regulation like NSD1, NFIX, FOXP1, and those in the PI3K-AKT pathway like PTEN, AKT3, TSC2, PPP2R5D. Five novel pathogenic variants were added by this study. NSD1-related Sotos syndrome was the most common disorder, seen in five patients. A causative variant was identified in 61.5% of patients who underwent only ES compared to the low yield of 11.1% in the CMA group. The molecular etiology could be confirmed in 13 subjects with OGID giving a diagnostic yield of 42%. The major burden was formed by autosomal dominant monogenic disorders. Hence, ES maybe a better first-tier genomic test rather than CMA in OGID.

A Potential Role of IL-6/IL-6R in the Development and Management of Colon Cancer

Colorectal cancer (CRC) is the third most frequent cancer worldwide and the second greatest cause of cancer deaths. About 75% of all CRCs are sporadic cancers and arise following somatic mutations, while about 10% are hereditary cancers caused by germline mutations in specific genes. Several factors, such as growth factors, cytokines, and genetic or epigenetic alterations in specific oncogenes or tumor-suppressor genes, play a role during the adenoma-carcinoma sequence. Recent studies have reported an increase in interleukin-6 (IL-6) and soluble interleukin-6 receptor (sIL-6R) levels in the sera of patients affected by colon cancer that correlate with the tumor size, suggesting a potential role for IL-6 in colon cancer progression. IL-6 is a pleiotropic cytokine showing both pro- and anti-inflammatory roles. Two different types of IL-6 signaling are known. Classic IL-6 signaling involves the binding of IL-6 to its membrane receptor on the surfaces of target cells; alternatively, IL-6 binds to sIL-6R in a process called IL-6 trans-signaling. The activation of IL-6 trans-signaling by metalloproteinases has been described during colon cancer progression and metastasis, involving a shift from membrane-bound interleukin-6 receptor (IL-6R) expression on the tumor cell surface toward the release of soluble IL-6R. In this review, we aim to shed light on the role of IL-6 signaling pathway alterations in sporadic colorectal cancer and the development of familial polyposis syndrome. Furthermore, we evaluate the possible roles of IL-6 and IL-6R as biomarkers useful in disease follow-up and as potential targets for therapy, such as monoclonal antibodies against IL-6 or IL-6R, or a food-based approach against IL-6.

New germline mutations in non-BRCA genes among breast cancer women of Mongoloid origin

In accordance with the Asian BRCA Consortium data, there is a significant difference in incidence rate of breast cancer depending on age, as well as spectrum and prevalence of BRCA1/2 mutations between Mongoloid (East Asian) and Caucasoid (European) people. However, European strategies to identify familial BC are still applied to the Asian population, including Russian Mongoloids (Khakas, Buryats, Tyvans and Yakuts and others). The main purpose of the study was to identify molecular changes associated with hereditary BC in Russian Mongoloid BC patients (Buryats). Thirty-nine patients were included in the study. Genomic DNA extracted from lymphocytes was used to prepare DNA-libraries. Target sequencing was designed to cover 27 genes, such as ATM, APC, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2 and others. Paired-end sequencing (2 × 150 bp) was conducted on a NextSeq 500 system (Illumina, USA). Three pathogenic mutations in non-BRCA genes were found (prevalence of 8%). The pathogenic mutations were found in the RAD51D and PTEN genes. The pathogenic variant in the RAD51D gene (rs137886232, NC_000017.10:g.33428366G>A, p.R141X) was observed in two unrelated individuals aged under 40. One of these patients had a family history of late-onset stomach cancer in second-degree relatives. The pathogenic mutation in the PTEN gene (rs786201044, NC_000010.10:g.89692922T>C, p.C136R) was observed in a 38 years old breast cancer patient with no family history. In our study, we first describe pathogenic mutations in RAD51D and PTEN genes found in young Buryat patients.

Genetics, diagnosis and treatment of Lynch syndrome: Old lessons and current challenges

Lynch syndrome (LS) is an autosomal dominant genetic disorder associated with germline mutations in DNA mismatch repair (MMR) genes. The carriers of pathogenic mutations in these genes have an increased risk of developing a colorectal cancer and/or LS-associated cancer. The LS-associated cancer types include carcinomas of the endometrium, small intestine, stomach, pancreas and biliary tract, ovary, brain, upper urinary tract and skin. The criteria for the clinical diagnosis of LS and the procedures of the genetic testing for identification of pathogenetic mutations carriers in MMR genes have long been known. A crucial point in the mutation detection analysis is the correct definition of the pathogenecity associated with MMR genetic variants, especially in order to include the mutation carriers in the endoscopy surveillance programs more suited to them. Therefore, this may help to improve the LS-associated cancer prevention programs. In the present review, we also report the recent discoveries in molecular genetics of LS, such as the new roles of MMR protein and immune response of MMR repair deficiency in colorectal cancer. Finally, we discuss the main therapeutic approaches, including immunotherapy, which represent a valid alternative to traditional therapeutic methods and extend the life expectancy of patients that have already developed LS-associated colorectal cancer.

Characterisation of mesenchymal colon tumour-derived cells in tumourspheres as a model for colorectal cancer progression

Cellular plasticity, the ability of cells to switch from an epitheial phenotype to a mesenchymal one and vice versa, plays a crucial role in tumour progression and metastases development. In 20-25% of patients with colon cancer and in 18% of patients with rectal cancer, metastases are present at the time of the first diagnosis. They are the first cause of colorectal cancer (CRC)-related mortality, defining stage IV CRC, which is characterized by a relatively short overall survival. We previously isolated two primary colon adenocarcinoma cell cultures that had undergone epithelial-mesenchymal transition (EMT), one with a high microsatellite instability phenotype (T88) and one with a chromosomal instability phenotype (T93). The aim of this study was to establish a model with which to study EMT, stemness features and cell plasticity in cancer progression and to examine the effects of incubation with lithium chloride (LiCl), a specific glycogen synthase kinase 3 β (GSK-3β) inhibitor, on these cellular processes. Indeed, GSK3β is an important regulator of cell survival, which promotes tumourigenesis in colon cells by facilitating the crosstalk between colorectal cancer pathways. Thus, we further characterized our system of adherent primary mesenchymal colon cancer cells and their paired tumourspheres by examining the expression and localisation of a panel of markers, including E- and N‑cadherin, CD133, CD44v6, aldehyde dehydrogenase 1 (ALDH1) and leucine-rich repeat‑containing G-protein coupled receptor 5 (LGR5). We also characterised the molecular features of these tumourspheres and examined their response to LiCl. Furthermore, we explored the effects of LiCl on cell motility and plasticity. We demonstrated that LiCl reduced cell migration, stemness features and cell plasticity. We also observed the atypical nuclear localisation of membrane proteins, including N‑cadherin, CD133 and CD44v6 in mesenchymal tumour cells. Of note, CD133 and CD44v6 appeared to localise at the plasma membrane in cells with a more epithelial phenotype, suggesting that the cytoplasmic/nuclear localisation of these proteins could favour and characterize cell plasticity in colorectal cancer progression.

Novel MSH2 splice-site mutation in a young patient with Lynch syndrome

Lynch Syndrome (LS) is associated with germline mutations in one of the mismatch repair (MMR) genes, including MutL homolog 1 (MLH1), MutS homolog 2 (MSH2), MSH6, PMS1 homolog 2, mismatch repair system component (PMS2), MLH3 and MSH3. The mutations identified in MMR genes are point mutations or large rearrangements. The point mutations are certainly pathogenetic whether they determine formation of truncated protein. The mutations that arise in splice sites are classified as ‘likely pathogenic’ variants. In the present study, a novel splicing mutation was identified, (named c.212-1g>a), in the MSH2 gene. This novel mutation in the consensus splice site of MSH2 exon 2 leads to the loss of the canonical splice site, without skipping in-frame of exon 2; also with the formation of 2 aberrant transcripts, due to the activation of novel splice sites in exon 2. This mutation was identified in a young patient who developed colon cancer at the age of 26 years and their belongs to family that met the ‘Revised Amsterdam Criteria’. The present study provided insight into the molecular mechanism determining the pathogenicity of this novel MSH2 mutation and it reaffirms the importance of genetic testing in LS.

Same MSH2 Gene Mutation But Variable Phenotypes in 2 Families With Lynch Syndrome: Two Case Reports and Review of Genotype-Phenotype Correlation

Lynch syndrome is an autosomal dominant syndrome that can be subdivided into Lynch syndrome I, or site-specific colonic cancer, and Lynch syndrome II, or extracolonic cancers, particularly carcinomas of the stomach, endometrium, biliary and pancreatic systems, and urinary tract. Lynch syndrome is associated with point mutations and large rearrangements in DNA MisMatch Repair (MMR) genes. This syndrome shows a variable phenotypic expression in people who carry pathogenetic mutations. So far, a correlation in genotype-phenotype has not been definitely established. In this study, we describe 2 Lynch syndrome cases presenting with the same genotype but different phenotypes and discuss possible reasons for this.

Characterization of novel, large duplications in the MSH2 gene of three unrelated Lynch syndrome patients

Lynch syndrome (LS) is associated with germ-line mutations in the DNA mismatch repair (MMR) genes, mainly MLH1, MSH2, MSH6, and PMS2. Most of genetic variants in the MMR genes predisposing to LS are point mutations, small deletions and insertions but large genomic rearrangements in the MMR genes also predisposing to Lynch syndrome. In this study, we report a novel, large rearrangement of the MSH2 gene, manifested by a duplication spanning a 14,846-bps region from intron 7 through intron 9. The breakpoints of this rearrangement were characterized by sequencing. Further analysis of the breakpoints revealed that this rearrangement was a product of Alu-mediated recombination. Finally, this large duplication was identified in three unrelated patients. Breakpoint analysis revealed the same junction fragments of introns 7 and 8 in the three index cases, suggesting a recurrent duplication or, alternatively, identity of the respective alleles by descent.

Incomplete Segregation of MSH6 Frameshift Variants with Phenotype of Lynch Syndrome

Lynch syndrome (LS), the most frequent form of hereditary colorectal cancer, involves mutations in mismatch repair genes. The aim of this study was to identify mutations in MSH6 from 97 subjects negative for mutations in MLH1 and MSH2. By direct sequencing, we identified 27 MSH6 variants, of which, nine were novel. To verify the pathogenicity of these novel variants, we performed in silico and segregation analyses. Three novel variants were predicted by in silico analysis as damaging mutations and segregated with the disease phenotype; while a novel frameshift deletion variant that was predicted to yield a premature stop codon did not segregate with the LS phenotype in three of four cases in the family. Interestingly, another frame-shift variant identified in this study, already described in the literature, also did not segregate with the LS phenotype in one of two affected subjects in the family. In all affected subjects of both families, no mutation was detected in other MMR genes. Therefore, it is expected that within these families, other genetic factors contribute to the disease either alone or in combination with MSH6 variants. We conclude that caution should be exercised in counseling for MSH6-associated LS family members.

Novel Implications in Molecular Diagnosis of Lynch Syndrome

About 10% of total colorectal cancers are associated with known Mendelian inheritance, as Familial Adenomatous Polyposis (FAP) and Lynch syndrome (LS). In these cancer types the clinical manifestations of disease are due to mutations in high-risk alleles, with a penetrance at least of 70%. The LS is associated with germline mutations in the DNA mismatch repair (MMR) genes. However, the mutation detection analysis of these genes does not always provide informative results for genetic counseling of LS patients. Very often, the molecular analysis reveals the presence of variants of unknown significance (VUSs) whose interpretation is not easy and requires the combination of different analytical strategies to get a proper assessment of their pathogenicity. In some cases, these VUSs may make a more substantial overall contribution to cancer risk than the well-assessed severe Mendelian variants. Moreover, it could also be possible that the simultaneous presence of these genetic variants in several MMR genes that behave as low risk alleles might contribute in a cooperative manner to increase the risk of hereditary cancer. In this paper, through a review of the recent literature, we have speculated a novel inheritance model in the Lynch syndrome; this could pave the way toward new diagnostic perspectives.

Common risk variants for colorectal cancer: an evaluation of associations with age at cancer onset

Common genetic risk variants for colorectal cancer (CRC) have been identified at approximately 40 loci by genome-wide association studies (GWAS). We investigated the association of these risk variants by age at onset of CRC using case-only and case-control analysis. A total of 1,962 CRC cases and 2,668 controls from two independent case-control studies conducted by Korea’s National Cancer Center were included in this study. We genotyped 33 GWAS-identified single-nucleotide polymorphisms (SNPs) associated with CRC risk. The risk allele in SNP rs704017, located at 10q22.3 in the ZMIZ1-AS1 gene, was consistently less frequent among CRC patients aged <50 years than among CRC patients aged ≥50 years in the case-only analysis (odds ratio (OR) = 0.78, 95% confidence interval (CI) = 0.66–0.92, P = 2.7 × 10⁻³, in an additive model), although this did not surpass the threshold for multiple testing. The direction of associations between rs704017 and CRC risk differed by age group in the combined case-control analysis (<50 years: OR = 0.77, 95% CI = 0.60–0.98, P = 0.03 and ≥50 years: OR = 1.13, 95% CI = 0.98–1.29, P = 0.09, in a dominant model); the p-values for heterogeneity (P_{heterogeneity} = 7.5 × 10⁻³) and for interaction were statistically significant (P_interaction = 7.8 × 10⁻³, in the dominant model). Our results suggest that the CRC susceptibility SNP rs704017 has a hereditary effect on onset age of CRC.

Phosphatase and Tensin Homolog Hamartoma Tumor Syndrome: A Case Report

INTRODUCTION

Phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) may manifest as one of four distinctive disorders: 1) Cowden syndrome; 2) Bannayan-Riley-Ruvalcaba syndrome; 3) Proteus syndrome; or 4) Proteus-like syndrome. Clinical features of PHTS commonly include multiple benign hamartomas of the skin and mucous membranes as well as macrocephaly. Despite the benign nature of the characteristic lesions, patients diagnosed with PHTS are at increased risk of certain cancers, most notably carcinomas of the breast, thyroid, and endometrium.

CASE PRESENTATION

A 28-year-old African-American female presented with generalized gingival overgrowth that involved the palate, gingival margins, and retromolar areas. The dorsal tongue also exhibited a generalized tissue hyperplasia. Based on clinical presentation, biopsies were performed for histology and genetic testing. Although histology revealed non-specific fibroepithelial hyperplasia, genetic testing revealed a novel heterozygous mutation of the PTEN gene (c.158_164dupTAGTAAG), believed to result in premature termination of the protein. The patient did not exhibit macrocephaly or extraoral skin lesions and did not have any obvious cognitive deficit.

CONCLUSIONS

This presentation of a Cowden syndrome-like scenario demonstrates that intraoral lesions may be the first symptom leading to a diagnosis of PHTS. Furthermore, the case shows that communication with and referral from the general dentist to specialists (e.g., oral pathologist, oral surgeon, or periodontist) can facilitate the establishment of a definitive diagnosis and allow for preventive screening and genetic counseling to aid in the treatment of secondary diseases, most notably associated cancers.

Multiple splenic hamartomas and familial adenomatous polyposis: a case report and review of the literature

Introduction

Splenoma or splenic hamartoma is a rare primary splenic tumor most often discovered radiologically and incidentally. Splenic hamartomas have a strong association with solid and hematological malignancies and, in rare cases, with tuberous sclerosis, but to the best of our knowledge no reports of splenic hamartomas associated with familial adenomatous polyposis have been documented, although it is recognized that familial adenomatous polyposis presents a variety of extracolonic manifestations.

Case presentation

We report on a very rare case of multiple splenic hamartomas in a 46-year-old white woman who had previously undergone surgery for restorative proctocolectomy for familial adenomatous polyposis. A computed tomography scan of her spleen revealed multiple small lesions which measured less than 1cm in diameter. A splenectomy was performed and a histologic examination of the splenectomy specimen revealed the presence of multiple hamartomas.

Conclusion

Incidence, differential diagnosis, diagnostic procedures, pathologic findings and treatment of splenic hamartomas are discussed here and hamartomas are considered in a differential diagnosis of splenic tumors. A splenectomy is indicated in cases where malignancy cannot be excluded and in cases of associated hematologic disorders. To the best of our knowledge our patient is the first reported case to have splenic hamartomas identified in a familial adenomatous polyposis-affected patient with mutation in exon 15 of the APC gene. At this time it is not possible to correlate with certainty our multiple splenic hamartomas and familial adenomatous polyposis case as a clinical manifestation of the mutation of APC gene; however, we believe that this case report could be important for further observation of similar cases in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/s13256-015-0627-3) contains supplementary material, which is available to authorized users.

Genetics, diagnosis and management of colorectal cancer (Review)

Colorectal cancer (CRC) is the third most common type of cancer worldwide and a leading cause of cancer death. Surgery represents the mainstay of treatment in early cases but often patients are primarily diagnosed in an advanced stage of disease and sometimes also distant metastases are present. Neoadjuvant therapy is therefore needed but drug resistance may influence response and concur to recurrent disease. At molecular level, it is a very heterogeneous group of diseases with about 30% of hereditary or familial cases. During colorectal adenocarcinomas development, epithelial cells from gastrointestinal trait acquire sequential genetic and epigenetic mutations in specific oncogenes and/or tumour suppressor genes, causing CRC onset, progression and metastasis. Molecular characterization of cancer associated mutations gives valuable information about disease prognosis and response to the therapy. Very early diagnosis and personalized care, as well as a better knowledge of molecular basis of its onset and progression, are therefore crucial to obtain a cure of CRC. In this review, we describe updated genetics, current diagnosis and management of CRC pointing out the extreme need for a multidisciplinary approach to achieve the best results in patient outcomes.

PTEN hamartoma tumor syndrome: clinical risk assessment and management protocol

The tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is an important phosphatase that counteracts one of the most critical cancer pathways: the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathways. Clinically, deregulation of PTEN function resulting in reduced PTEN expression and activity is implicated in human diseases. Cowden syndrome (CS) is an autosomal dominant disorder characterized by benign and malignant tumors. CS-related individual features occur commonly in the general population. Approximately 25% of patients diagnosed with CS have pathogenic germline PTEN mutations, which increase lifetime risks of breast, thyroid, uterine, renal and other cancers. PTEN testing and intensive cancer surveillance allow for early detection and treatment of these cancers for mutation positive patients and their relatives. In this review, we highlight our current knowledge of germline PTEN mutations in relation to human disease. We review current clinical diagnosis and management recommendations for PHTS including recent discoveries in understanding PTEN function regulation and how this can be exploited therapeutically.