Genotypic and Phenotypic Characteristics of Hereditary Colorectal Cancer

The genomics of sporadic and hereditary colorectal cancer

Colorectal cancer (CRC) is a leading cause of cancer deaths worldwide. Over the past three decades, extensive efforts have sought to elucidate the genomic landscape of CRC. These studies reveal that CRC is highly heterogeneous at the molecular level, with different subtypes characterised by distinct somatic mutational profiles, epigenetic aberrations and transcriptomic signatures. This review summarises our current understanding of the genomic and epigenomic alterations implicated in CRC development and progression. Particular focus is given to how characterisation of CRC genomes is leading to more personalised approaches to diagnosis and treatment.

Sebaceomas in a Muir-Torre-like Phenotype in a Patient with MUTYH-Associated Polyposis

This case report describes a case of a patient with MUTYH-associated polyposis (MAP), who presented with multiple sebaceomas in a Muir-Torre-like phenotype. MAP is caused by mutations in MUTYH, a base excision repair gene responsible for detecting and repairing the 8-oxo-G:A transversion caused by reactive oxygen species. MAP is associated with an increased risk of developing adenomatous polyps and colorectal cancer. Muir-Torre syndrome is a clinical phenotype of Lynch syndrome, which presents with multiple cutaneous sebaceous neoplasms. Lynch syndrome, like MAP, increases the likelihood of developing colorectal cancer but with a different pathogenesis and mode of inheritance. This case demonstrates that in a patient presenting with multiple sebaceous neoplasms, further workup and genetic testing may be indicated, not only for Muir-Torre and Lynch syndrome but also for MAP.

Performance reporting design in artificial intelligence studies using image-based TNM staging and prognostic parameters in rectal cancer: a systematic review

PURPOSE

The integration of artificial intelligence (AI) and magnetic resonance imaging in rectal cancer has the potential to enhance diagnostic accuracy by identifying subtle patterns and aiding tumor delineation and lymph node assessment. According to our systematic review focusing on convolutional neural networks, AI-driven tumor staging and the prediction of treatment response facilitate tailored treat-ment strategies for patients with rectal cancer.

METHODS

This paper summarizes the current landscape of AI in the imaging field of rectal cancer, emphasizing the performance reporting design based on the quality of the dataset, model performance, and external validation.

RESULTS

AI-driven tumor segmentation has demonstrated promising results using various convolutional neural network models. AI-based predictions of staging and treatment response have exhibited potential as auxiliary tools for personalized treatment strategies. Some studies have indicated superior performance than conventional models in predicting microsatellite instability and KRAS status, offer-ing noninvasive and cost-effective alternatives for identifying genetic mutations.

CONCLUSION

Image-based AI studies for rectal can-cer have shown acceptable diagnostic performance but face several challenges, including limited dataset sizes with standardized data, the need for multicenter studies, and the absence of oncologic relevance and external validation for clinical implantation. Overcoming these pitfalls and hurdles is essential for the feasible integration of AI models in clinical settings for rectal cancer, warranting further research.

Identification of a novel CNV at the APC gene in a Chinese family with familial adenomatous polyposis

Introduction: Familial adenomatous polyposis (FAP) is the second most commonly inherited colorectal cancer (CRC) predisposition caused by germline mutations within the adenomatous polyposis coli (APC) gene. The molecular defects and clinical manifestations of two FAP families were analyzed, and individual prevention strategies suitable for mutation carriers in different families were proposed. Methods and results: The pathogenic gene mutations were identified among the two families using whole-exome sequencing and verified with Sanger sequencing or quantitative polymerase chain reaction (qPCR). One novel (GRCh37:Chr5: 112145676-112174368, del, 28,692 bp) and a known (c.C847T:p.R283X) mutation in the APC gene were pathogenic mutations for FAP, according to the sequencing data and tumorigenesis pattern among the family members. The two mutations led to a premature translational stop signal, synthesizing an absent or disrupted protein product. Conclusion: Our findings expand the known germline mutation spectrum of the APC gene among the Chinese population. This reaffirms the importance of genetic testing in FAP. Genetic consultation and regular follow-ups are necessary for the individualized treatment of cancer-afflicted families with APC expression deficiency. Additional work is required to develop safe and effective chemotherapy and immunotherapy for FAP based on the mutation type.

An update of the variant spectrum of the APC gene in Iranian familial adenomatous polyposis patients

Familial adenomatous polyposis (FAP) is an autosomal dominant colorectal cancer syndrome that is characterized by the development of multiple adenomas in the colon and rectum with high penetrance rates. This disease has specific features like the occurrence of pathogenic variations in the APC gene and diverse FAP phenotypes due to the occurrence region. In this study we aimed to evaluate pathogenic variants in exons of the APC gene in Iranian patients with FAP. A total of 35 FAP individuals were referred to the gastroenterology ward of Taleghani Hospital. As the aim of the study was to study the germline variations in the participants, the peripheral blood was collected and after the DNA extraction, PCR, and Sanger sequencing processes for the APC gene, the results were evaluated by the ACMG classification guidelines to report their pathogenicity. Accordingly, out of eight specific detected variants, three of them were novel, and the rest were reported previously. These eight variants were all truncating protein and pathogenic, and they were limited to 849-1378 codons. Overall, detected variants revealed discrepancies and parallels with previous reported cases in terms of quantity, occurrence region, and association with demographic and clinicopathological characteristics of patients. The spectrum of detected variants and the patient's phenotype showed distinct characteristics, such as occurrence in specific regions and the absence of extracolonic symptoms like Congenital hypertrophy of the retinal pigment epithelium (CHRPE). These findings open the path to comprehending the typical symptoms, their rarity, and their occurrence in the Iranian population and also due to the facts, we found that the studying of the APC gene alone for diagnosing FAP disease is not sufficient, and considering other genes are completely rational in the case of sequencing and studying the variants.

Case report: POLE (P286R) mutation in a case of recurrent intestinal leakage and its treatment

In recent years, although new drugs and molecular markers have been used to treat metastatic colorectal cancer, there has been little progress in the immunotherapy of advanced colon cancer. The development of sequencing and multiomics technology helps us classify patients more accurately, and then find patients who may benefit from immunotherapy. The development of this advanced technology and immunotherapy based on new targets may herald a new era in the treatment of metastatic colorectal cancer. It is well known that colorectal cancer with dmmr/msi-h phenotype is sensitive to immunotherapy, yet the POLE mutation is the MSS phenotype in colorectal tumors but is also an effective target for immunotherapy. This paper describes a case of recurrent intestinal leakage that required multiple surgical procedures. A high-grade colon adenocarcinoma was identified on surgical histopathology after 18 months, and bevacizumab combined with oxaliplatin and capecitabine proved ineffective against this cancer. An analysis of gene expression indicated that POLE (P286R) mutation, TMB 119.333 mutation per 100 MB, and immune checkpoint inhibitor treatment had a significant impact. This case reminds us that the existence of malignant tumors should be considered for patients with repeated intestinal leakage, and emphasizes the importance of gene detection in the treatment of malignant tumors and the significance of POLE mutations in colorectal cancer.

Reduced expression of alanyl aminopeptidase is a robust biomarker of non-familial adenomatous polyposis and non-hereditary nonpolyposis colorectal cancer syndrome early-onset colorectal cancer

BACKGROUND

Early-onset colorectal cancer (EOCRC) has been increasing in incidence worldwide but its genomic pathogenesis is mostly undetermined. This study aimed to identify robust EOCRC-specific gene expression patterns in non-familial adenomatous polyposis (FAP) and non-hereditary nonpolyposis colorectal cancer syndrome (HNPCC) EOCRC.

METHOD

We first performed gene expression profiling analysis using RNA sequencing of discovery cohort comprised of 49 EOCRC (age <50) and 50 late-onset colorectal cancer (LOCRC) (age >70) specimens. To obtain robust gene expression data from this analysis, we validated differentially expressed genes (DEGs) through TCGA cohort (EOCRC:59 samples, LOCRC:229 samples) and our validation cohort (EOCRC:72 samples, LOCRC:43 samples) using real-time RT-PCR. After the validation of DEGs, we validated the selected gene at protein levels using Western blotting. To identify whether genomic methylation regulates the expression of a particular gene, we selected methylation sites using The Cancer Genome Atlas (TCGA) datasets and validated them by pyrosequencing in our validation cohort.

RESULTS

The EOCRC patients included in this study had significantly more prominent family history of cancer than the LOCRC patients (23 [46.9%] vs. 13 [26%], p = 0.050). Alanyl aminopeptidase (ANPEP) was significantly downregulated in the EOCRC tissues (FC = 1.78, p = 0.0007) and was also commonly downregulated in the TCGA cohort (FC = -1.08, p = 0.0021). Moreover, the ANPEP mRNA and protein expression levels were significantly downregulated in the EOCRC tissues of our validation cohort (p = 0.037 and 0.027). In comparisons of the normal and tumor tissues in public datasets, the ANPEP level was significantly lower in the tumor tissue in the TCGA dataset (p < 2.2 × 10^-16 ) and GSE196006 dataset (p = 0.0005). Furthermore, the ANPEP expression level did not show a decreasing tendency at a young age in the normal colon tissue of the GTEx dataset. Lastly, the hypermethylation of cg26222247 in ANPEP was identified to be weakly associated with reduced ANPEP expression in our EOCRC cohort.

CONCLUSION

The reduced expression of ANPEP was identified as a novel biomarker of non-FAP and non-HNPCC EOCRC.

Molecular Analyses in Peritoneal Metastasis from Colorectal Cancer: A Review-An English Version

Despite a trend showing continued improvement in survival by combing targeted agents in colorectal cancer, the improvement was limited, and clinically meaningful benefits were not achieved in peritoneal metastasis. The role of cytoreductive surgery (CRS) and proportion of the benefit from hyperthermic intraperitoneal chemotherapy (HIPEC) have been questioned. The PRODIGE 7 study aimed to assess the specific contribution of HIPEC to the survival benefit of peritoneal metastasis from colorectal cancer (CRC-PM) by grouping CRS alone versus CRS with oxaliplatin-based HIPEC, but failed to show any survival improvement. Of these criticisms, oxaliplatin resistance was suggested as the main cause of the negative result. In this regard, the relative resistance to oxaliplatin in consensus molecular subtype 4 colorectal cancer (CRC) is of great interest. Recent treatments for metastatic CRC have gradually moved to precision medicine based on individual biological information through high-throughput technology such as next generation sequencing. This review aimed to provide an overview of the current status of studies reporting the molecular knowledge of CRC-PM.

A Previously Unrecognized Molecular Landscape of Lynch Syndrome in the Mexican Population

Lynch syndrome (LS) is the main hereditary colorectal cancer syndrome. There have been few reports regarding the clinical and molecular characteristics of LS patients in Latin America; this is particularly true in the Mexican population, where no information is available. The present study aims to describe the clinical and molecular spectrum of variants in a cohort of patients diagnosed with LS in Mexico. We present a retrospective analysis of 412 patients with suspected LS, whose main site of cancer diagnosis was the colon (58.25%), followed by the endometrium (18.93%). Next-generation sequencing analysis, with an extensive multigene panel, showed that 27.1% (112/414) had a variant in one of the genes of the mismatch repair pathway (MMR); 30.4% (126/414) had a variant in non-MMR genes such as CHEK2, APC, MUTYH, BRCA1, and BRCA2; and 42.5% (176/414) had no genetic variants. Most of the variants were found in MLH1. Pathogenic variants (PVs) in MMR genes were identified in 65.7% (96/146) of the total PVs, and 34.24% (45/146) were in non-MMR genes. Molecular and clinical characterization of patients with LS in specific populations allowed personalized follow-up, with the option for targeted treatment with immune checkpoint inhibitors and the development of public health policies. Moreover, such characterization allows for family cascade testing and consequent prevention strategies.

Direction of diagnosis and treatment improvement in colorectal cancer

Background: Cancer is a major public health problem and the leading cause of death in Korea since 2000. Colorectal cancer is the third leading cause of cancer-related death. Therefore, early detection through screening, surgical techniques improvement, anticancer drugs, adjuvant treatment, and medical resources advancement is important to reduce colorectal cancer-related mortality.Current Concepts: In Korea, the 5-year relative survival rate of patients with colorectal cancer is approximately mid-70%, which is superior to other developed countries, such as the United States, United Kingdom, and Japan, with 60% to 68% because of the well performed screening program and technical improvement. Efforts are underway to conduct active endoscopic treatment for early colorectal cancer and identify cases requiring surgery. Minimally invasive surgery has evolved beyond conventional applications into disease-specific methods, and the robotic system has an important role for evolvement. Performing metastatic colorectal cancer efforts is necessary to improve the survival rate through active surgical treatment and gene therapy.Discussion and Conclusion: Eventually, the role of the patient’s genetic information in diagnosing and treating colorectal cancer is expected to increase. In some cases, diagnosing colorectal cancer using a non-invasive method is already realized. Active surgical treatment based on personal characteristics contributes in improving the treatment outcomes for difficult-to-treat metastatic colorectal cancer. After the period of overall colorectal cancer treatment results improvement, we will undertake the precision treatment era.

Molecular analyses of peritoneal metastasis from colorectal cancer

Background: Despite a trend showing continued improvement in survival by combing targeted agents for colorectal cancer (CRC), the improvement observed is limited. Moreover, clinically relevant benefits were not achieved in peritoneal metastasis cases. The role of cytoreductive surgery (CRS) and the benefits of hyperthermic intraperitoneal chemotherapy (HIPEC) have been questioned. This review aimed to provide an overview of the current status of the studies reporting on the molecular knowledge of peritoneal metastasis from CRC (CRC-PM).Current Concepts: The PRODIGE 7 study was performed to assess the specific contributions of HIPEC to the survival benefit in CRC-PM cases by comparing CRS treatment alone and CRS with oxaliplatin-based HIPEC. However, this study did not reveal any survival improvement, and oxaliplatin resistance was suggested as the main cause of this negative outcome. Hence, the relative resistance to oxaliplatin in consensus molecular subtype (CMS) 4 CRC is of great interest.Discussion and Conclusion: Recent treatments for metastatic CRC have gradually moved to precision medicine based on individual biological information through high-throughput technology, such as next-generation sequencing. In the transcriptome study, CRC-PM was identified as an almost homogeneous CMS4 classification, which is known to have strong resistance to oxaliplatin-based chemotherapy. These results suggest the need to clarify complex sub-signal transmission pathways derived from transcriptome or proteome studies of CRC-PM. Finally, to compare two studies, it is necessary to establish a representative patient group and consider standardized sample collection, treatment, and analysis.