Differential clinicopathological and molecular features within late-onset colorectal cancer according to tumor location

Clinical implications of genetic testing in familial intermediate and late-onset colorectal cancer

The genetic background of familial, late-onset colorectal cancer (CRC) (i.e., onset > age 50 years) has not been studied as thoroughly as other subgroups of familial CRC, and the proportion of families with a germline genetic predisposition to CRC remains to be defined. To define the contribution of known or suggested CRC predisposition genes to familial late-onset CRC, we analyzed 32 well-established or candidate CRC predisposition genes in 75 families with late-onset CRC. We identified pathogenic or likely pathogenic variants in five patients in MSH6 (n = 1), MUTYH (monoallelic; n = 2) and NTHL1 (monoallelic; n = 2). In addition, we identified a number of variants of unknown significance in particular in the lower penetrant Lynch syndrome-associated mismatch repair (MMR) gene MSH6 (n = 6). In conclusion, screening using a comprehensive cancer gene panel in families with accumulation of late-onset CRC appears not to have a significant clinical value due to the low level of high-risk pathogenic variants detected. Our data suggest that only patients with abnormal MMR immunohistochemistry (IHC) or microsatellite instability (MSI) analyses, suggestive of Lynch syndrome, or a family history indicating another cancer predisposition syndrome should be prioritized for such genetic evaluations. Variants in MSH6 and MUTYH have previously been proposed to be involved in digenic or oligogenic hereditary predisposition to CRC. Accumulation of variants in MSH6 and monoallelic, pathogenic variants in MUTYH in our study indicates that digenic or oligogenic inheritance might be involved in late-onset CRC and warrants further studies of complex types of inheritance.

Magnetic Resonance Image under the Low-Rank Matrix Denoising Algorithm in Evaluating the Efficacy of Neoadjuvant Chemo-Radiotherapy for Rectal Cancer

This study was to explore the application value of magnetic resonance imaging (MRI) images obtained by low-rank matrix recovery algorithm (LRMR algorithm) in evaluating the curative effect of rectal cancer patients receiving the neoadjuvant chemo-radiotherapy (nCRT). In this study, an image denoising model was designed based on the LRMR algorithm, the original low-rank data matrix was recovered from the error, and the low-rank matrix was restored by solving the optimal kernel norm, so as to effectively separate the image data information and the interference noise. In addition, the model was applied to 60 patients with rectal cancer who received nCRT to extract the texture parameters and lesion-related data from the MRI images. The results showed that the MRI images optimized by LRMR algorithm were clearer than the original images, contained less excess noise, and had improved imaging accuracy and image quality. The results of typical cases suggested that the front of the rectal wall membrane of a patient in the T-downstage group was not smooth before treatment, the internal angiography was blurred, and the wall membrane was thickened, but the wall membrane became thinner after treatment, the highest position was reduced from 1.46 cm to 0.38 cm, the average value of the apparent diffusion coefficient (ADC) increased from 0.732 × 10−3 mm2/s to 1.196 × 10−3 mm2/s, and the lesion tissue was thicker. It was found that the height, length, and ADC of the lesion after the nCRT showed statistically great difference in contrast to the values before the treatment $\left(P<0.05\right)$ . Such results indicated that the nCRT showed obvious effects in the clinical treatment of rectal cancer. In short, the LRMR algorithm could remove the interference noise in the MRI image, and from the information about rectal cancer tumor lesions extracted from that, the height value and length value of tumor lesions in patients given neoadjuvant chemo-radiotherapy were reduced compared with those before treatment, and the apparent diffusion coefficient value was increased, indicating that neoadjuvant chemo-radiotherapy has a significant effect in the clinical treatment of rectal cancer.

Right and Left Colorectal Cancer: Differences in Post-Surgical-Care Outcomes and Survival in Elderly Patients

Simple Summary

The objective of this investigation is to analyze the differences between right and left colon cancer survival and test if these differences have transcendental importance for assistance to improve the survival and quality care of these patients. The results show that both entities are significantly different in terms of evolution, progression, complications and survival. Patients with right colon cancer have a worse prognosis, even in the early stages of the disease, due to more advanced N stages, a larger tumor size, more frequently poorly differentiated tumors and a greater positivity of lymphovascular invasion than left colon cancer. Improvement of the prognosis can be implemented mainly by reducing the specific mortality of colon cancer by achieving early detection and also stratified and personalized by location and age of onset, as well as surgical and oncological treatment of these patients.

Abstract

(1) There is evidence of the embryological, anatomical, histological, genetic and immunological differences between right colon cancer (RCC) and left colon cancer (LCC). This research has the general objective of studying the differences in outcome between RCC and LCC. (2) A longitudinal analytical study with prospective follow-up of the case–control type was conducted from 1 January 2010 to 31 December 2017 including 398 patients with 1:1 matching, depending on the location of the tumor. Inclusion criteria: programmed colectomies, 15 cm above the anal margin, adults and R0 surgery. (3) Precisely 6.8% of the exitus occurred in the first 6 months of the intervention. At 6 months, patients with LCC presented a mean survival of 7 months higher than RCC (p = 0.028). In the first stages, it can be observed that most of the exitus are for patients with RCC (stage I p = 0.021, stage II p = 0.014). In the last stages, the distribution of the deaths does not show differences between locations (stage III p = 0.683, stage IV p = 0.898). (4) The results show that RCC and LCC are significantly different in terms of evolution, progression, complications and survival. Patients with RCC have a worse prognosis, even in the early stages of the disease, due to more advanced N stages, larger tumor size, more frequently poorly differentiated tumors and a greater positivity of lymphovascular invasion than LCC.

Copy number variation of ubiquitin- specific proteases genes in blood leukocytes and colorectal cancer

Ubiquitin-specific proteases (USPs) play important roles in the regulation of many cancer-related biological processes. USPs copy number variation (CNVs) may affect the risk and prognosis of colorectal cancer (CRC). We detected CNVs of USPs genes in 468 matched CRC patients and controls, estimated the associations between the USPs genes CNVs and CRC risk and prognosis and their interactions with environmental factors on CRC risk. Finally, we generated five CRC risk predictive models with different CNVs patterns combining with environmental factors (EF). We identified significant association between CYLD deletion and CRC risk (ORadj = 4.18, 95% CI: 2.03-8.62), significant association between USP9X amplification and CRC risk (ORadj = 2.30, 95% CI: 1.48-3.57), and significant association between USP11 deletion and CRC risk (ORadj = 3.49, 95% CI: 1.49-8.64). There were significant gene-environment and gene-gene interactions on CRC risk. The area under the receiver operating characteristic curve (AUC) of EF + SIG (deletion of CYLD and USP11, amplification of USP9X) model was significantly larger than any other models (AUC = 0.75, 95% CI: 0.74-0.77). We did not identify significant associations between CNVs of the three genes and CRC prognosis. CNVs of CYLD, USP9X, and USP11 are significantly associated with the risk of CRC. Gene-gene and gene-environment interactions might also play an important role in the development of CRC.

Clinical and Genetic Characteristics of Colorectal Cancer in Persons under 50 Years of Age: A Review

BACKGROUND

The incidence of colorectal cancer (CRC) in persons under the age of 50 years (EOCRC) is increasing even as the incidence of CRC in persons over age 50 is decreasing. This has led to recommendations to lower the age of CRC screening to age 45. It is not clear whether EOCRC is identical to CRCs in older patients or whether there are distinctive features between the two groups.

AIMS AND METHODS

We reviewed the literature on the clinical and genetic aspects of EOCRC.

RESULTS

We found that there is an increased likelihood of a strong genetic basis for EOCRC, but that at least 80% of cases do not come from the known high-penetrance cancer syndromes. Early-onset CRCs tend to occur in the distal colon or rectum, are more likely to be detected due to cancer-related symptoms, appear to be increasing in whites more than non-whites on a population-wide analysis, and are more likely to present in an advanced stage of disease. There are some unique genetic features of EOCRC, including an increased proportion of tumors with LINE-1 hypomethylation, and combined chromosomal and microsatellite stability.

CONCLUSIONS

EOCRC deserves additional attention because of the high number of life years at risk with EOCRC, and the implications for earlier CRC screening. Additional focus is needed on determining whether some cases of EOCRC have a unique mechanistic basis.

Clinical and Molecular Comparative Study of Colorectal Cancer Based on Age-of-onset and Tumor Location: Two Main Criteria for Subclassifying Colorectal Cancer

Our aim was to characterize and validate that the location and age of onset of the tumor are both important criteria to classify colorectal cancer (CRC). We analyzed clinical and molecular characteristics of early-onset CRC (EOCRC) and late-onset CRC (LOCRC), and we compared each tumor location between both ages-of-onset. In right-sided colon tumors, early-onset cases showed extensive Lynch syndrome (LS) features, with a relatively low frequency of chromosomal instability (CIN), but a high CpG island methylation phenotype. Nevertheless, late-onset cases showed predominantly sporadic features and microsatellite instability cases due to BRAF mutations. In left colon cancers, the most reliable clinical features were the tendency to develop polyps as well as multiple primary CRC associated with the late-onset subset. Apart from the higher degree of CIN in left-sided early-onset cancers, differential copy number alterations were also observed. Differences among rectal cancers showed that early-onset rectal cancers were diagnosed at later stages, had less association with polyps, and more than half of them were associated with a familial LS component. Stratifying CRC according to both location and age-of-onset criteria is meaningful, not only because it correlates the resulting categories with certain molecular bases, but with the confirmation across larger studies, new therapeutical algorithms could be defined according to this subclassification.