Hereditary diffuse gastric cancer: One family’s story

PATHOLOGICAL SIGNIFICANCE OF CDH1/E-CADHERIN GERMLINE SEQUENCE VARIANTS IN BREAST CANCER PATIENTS

BACKGROUND

Germline alterations of the CDH1 (E-cadherin) tumor suppressor gene have been reported in several epithelial malignancies like hereditary diffuse gastric cancer and lobular breast cancer. E-cadherin plays a central role in proliferation, maintenance of cell-to-cell adhesion, polarity, and epithelial-mesenchymal transition of tissue cells. It is necessary to analyze the impact of the CDH1 germline sequence variants on protein and predict its clinical significance in breast cancer (BC) progression. The aim of the current study was to evaluate the impact and association of CDH1 gene potentially pathogenic variants/likely pathogenic variants (PVs/LPVs) with the initiation and progression of BC.

MATERIALS AND METHODS

In this study, the clinical data of 200 BC patients have been analyzed based on the type of BC, age, grade, stage, hormonal status, and risk factors. Blood samples from 50 healthy donors were used as a control. Furthermore, CDH1 gene molecular analysis, along with in silico analysis, was provided to assess the invasiveness and progression of BC caused by the E-cadherin protein.

RESULTS

Four variants were identified by genetic screening within the CDH1 gene that included variations in exons 7, 8, 10, 11, and 13. Exon 10 had splice site mutation at position c.1337C>A, affecting the protein structure. In exon 11, there was an insertion of T base at position 1669, resulting in truncated protein compared to a normal one that can lead to the disease-causing non- sense-mediated decay and exon 13 variant c.2076T>C has already known polymorphism. In silico analysis of CDH1 showed the presence of the different variants that indicated the overall disruption of protein structure and function.

CONCLUSIONS

The further functional analysis of these variants and their association with BC can be ensured by increasing the sample size and in vivo studies using mouse models.

Significance of E-cadherin Gene Mutations in Patients With Hereditary Diffuse Gastric Cancer Syndrome: A Systematic Review

Gastric cancer is the third-most fatal cancer in the world. Though over the years, we saw patients mostly with intestinal type accounting for the highest mortality rate, the recent rise of the diffuse form with germline E-cadherin (CDH1) mutations has added a whole new level of interest to study in detail about the association between CDH1 and diffuse gastric cancer (DGC). This introduced a set guideline formulated by Internal Gastric Cancer Linkage Consortium (IGCLC) for patients with family history of diffuse gastric cancer and invasive lobular breast cancer (ILBC). The analysis of this link was also important to set proper management protocol for patients who were CDH1 mutation carriers which now involves genetic counselling, endoscopic surveillance and screening and prophylactic total gastrectomy (PTG). The study was conducted in accordance to the 'PRISMA guidelines for reporting systematic review and meta-analysis'. Peer-reviewed studies were included from the PubMed database and relevant articles were selected to be included in the study. Appropriate inclusion/exclusion criteria with free full text English articles were applied while selecting the articles. A total of 10 studies on review with different study populations showed that of the 42 patients who were diagnosed with diffuse gastric cancer, 88% of them showed a positive germline E-cadherin gene mutation and 100% of the CDH1 mutation carriers showed microscopic changes of signet ring cell adenocarcinoma of the stomach. The beneficial effects of PTG with better survival rates and low mortality rates has outweighed other treatment modalities. Laparoscopic approach has proved to be more useful and a safer approach for gastrectomy surgeries with better post-operative management. The need for prophylactic mastectomy is also increased in the recent times and thus this requires a new set of guidelines for ILBC patients with hereditary diffuse gastric cancer (HDGC) syndrome.

Gastric carcinoma: Insights into risk factors, methods of diagnosis, possible lines of management, and the role of primary care

Gastric carcinoma represents the second most common type of malignancy that contributes to cancer-related mortality worldwide. However, the geographic incidence of gastric carcinoma had changed over the last few decades, possibly due to increased hygiene, increased awareness of the importance of healthy nutrition, and increased rates of eradication of Helicobacter pylori infection. Gastric carcinoma consists of two pathological variants, intestinal and diffuse. Early cases of gastric carcinoma may be asymptomatic. However, advanced cases may present with significant weight loss, dysphagia, abdominal pain, vomiting, and even severe upper gastrointestinal bleeding. Patients at high risk of developing gastric carcinoma should be adequately screened at primary healthcare centers for early detection and effective management. Lines of treatment vary according to the stage of the disease but surgical resection of the tumor with regional lymphadenectomy remains the gold standard of therapy. This review sheds light on gastric carcinoma given the recent trends regarding its prevalence, risk factors, types, clinical picture, methods of diagnosis, possible lines of management, and the role of primary care.

CDH1 Mutation Distribution and Type Suggests Genetic Differences between the Etiology of Orofacial Clefting and Gastric Cancer

Pathogenic variants in CDH1, encoding epithelial cadherin (E-cadherin), have been implicated in hereditary diffuse gastric cancer (HDGC), lobular breast cancer, and both syndromic and non-syndromic cleft lip/palate (CL/P). Despite the large number of CDH1 mutations described, the nature of the phenotypic consequence of such mutations is currently not able to be predicted, creating significant challenges for genetic counselling. This study collates the phenotype and molecular data for available CDH1 variants that have been classified, using the American College of Medical Genetics and Genomics criteria, as at least ‘likely pathogenic’, and correlates their molecular and structural characteristics to phenotype. We demonstrate that CDH1 variant type and location differ between HDGC and CL/P, and that there is clustering of CL/P variants within linker regions between the extracellular domains of the cadherin protein. While these differences do not provide for exact prediction of the phenotype for a given mutation, they may contribute to more accurate assessments of risk for HDGC or CL/P for individuals with specific CDH1 variants.

Effect of docetaxel-loaded lipid microbubble in combination with ultrasound-triggered microbubble destruction on the growth of a gastric cancer cell line

Although gastric cancer therapy has been improved, more efficient treatment strategies still need to be developed. In the present study, a docetaxel (DOC)-loaded lipid microbubble (DLLD) was prepared and the effect of DLLD combined with ultrasound-triggered microbubble destruction (UTMD) on the growth of a gastric cancer cell line was investigated. The following four groups were included in the present study: Control, DOC, DLLD and DLLD plus UTMD. The determined entrapment efficiency of DLLD is 76±3.5%. The present study demonstrated that treatment with DLLD plus UTMD could significantly inhibit the growth of the cultured gastric cancer cell line BGC-823 via arresting the cell cycle in G₂/M phase, inhibiting cell DNA synthesis, promoting cell apoptosis and disrupting mitochondrial membrane potential, as compared with treatment with DOC or DLLD alone. Furthermore, the expression of p53, p21 and Bax were identified to be significantly upregulated, while that of Bcl-2 was significantly downregulated in the DLLD plus UTMD group. Therefore, treatment with DLLD plus UTMD was more efficient in inhibiting cell proliferation and inducing cell apoptosis in the gastric cancer cell line, when compared with treatment with DOC or DLLD alone, suggesting that DLLD plus UTMD could serve as a promising strategy for the treatment of gastric cancer.

Diffuse Gastric Cancer: A Summary of Analogous Contributing Factors for Its Molecular Pathogenicity

Gastric cancer is the third leading cause of cancer-related deaths and ranks as the fifth most common cancer worldwide. Incidence and mortality differ depending on the geographical region and gastric cancer ranks first in East Asian countries. Although genetic factors, gastric environment, and Helicobacter pylori infection have been associated with the pathogenicity and development of intestinal-type gastric cancer that follows the Correa’s cascade, the pathogenicity of diffuse-type gastric cancer remains mostly unknown and undefined. However, genetic abnormalities in the cell adherence factors, such as E-cadherin and cellular activities that cause impaired cell integrity and physiology, have been documented as contributing factors. In recent years, H. pylori infection has been also associated with the development of diffuse-type gastric cancer. Therefore, in this report, we discuss the host factors as well as the bacterial factors that have been reported as associated factors contributing to the development of diffuse-type gastric cancer.

Molecular biology as a tool for the treatment of cancer

Cancer is a genetic disease characterized by uncontrolled cell growth and metastasis. Cancer can have a number of causes, such the activation of oncogenes, the inactivation of tumor-suppressing genes, mutagenesis provoked by external factors, and epigenetic modifications. The development of diagnostic tools and treatments using a molecular biological approach permits the use of sensitive, low-cost, noninvasive tests for cancer patients. Biomarkers can be used to provide rapid, personalized oncology, in particular the molecular diagnosis of chronic myeloid leukemia, and gastric, colon, and breast cancers. Molecular tests based on DNA methylation can also be used to direct treatments or evaluate the toxic effects of chemotherapy. The adequate diagnosis, prognosis, and prediction of the response of cancer patients to treatment are essential to ensure the most effective therapy, reduce the damaging effects of treatment, and direct the therapy to specific targets, and in this context, molecular biology has become increasingly important in oncology. In this brief review, we will demonstrate the fundamental importance of molecular biology for the treatment of three types of cancer-chronic myeloid leukemia, hereditary diffuse gastric cancer, and astrocytomas (sporadic tumors of the central nervous system). In each of these three models, distinct biological mechanisms are involved in the transformation of the cells, but in all cases, molecular biology is fundamental to the development of personalized analyses for each patient and each type of neoplasia, and to guarantee the success of the treatment.