Approach to early-onset colorectal cancer: Clinicopathological, familial, molecular and immunohistochemical characteristics

Early-Onset Colorectal Cancer-A Retrospective Study from a Tertiary Referral Hospital in Romania

Early-onset colorectal cancer emerges as a distinctive clinical and biological entity and is generally defined as the onset of colon or rectal neoplasia before the age of 50. Several reports describe an increasing incidence worldwide of colorectal cancers occurring in individuals younger than 50 years, along with particular histologic and molecular features. Although heredity may be an explanation in some cases with young-onset colorectal cancer, other driving factors remain partially unknown. The present study explores demographic, clinical, and pathological features within a group of patients diagnosed with colorectal cancer before the age of 50. It is a retrospective survey based on data collected between 2017 and 2023 within three surgical departments from a tertiary Romanian hospital. The clinical and pathological features we identified (later-stage disease, distal colon tumor localization, mucinous histology) are mainly superimposed with the existing data in the literature regarding this pathology. In order to lower the burden that colorectal neoplasia diagnosed in the young implies, a change of paradigm should be made in terms of establishing effective and targeted screening programs but also in the direction of enhancing complex clinical, pathological, and molecular diagnosis.

Clinical and pathological characteristics of early-onset colorectal cancer in South Korea

Background

Early-onset colorectal cancer (EOCRC) may differ by race and ethnicity, and recently South Korea has witnessed a surge in cases. We aimed to evaluate the clinical and pathological features of patients with EOCRC, and to determine the predictors of overall survival.

Methods

In this retrospective study, EOCRC was defined as CRC diagnosed in patients aged < 50 years, and late-onset CRC was defined as CRC diagnosed in those over 75 years of age. The clinical and pathological characteristics of patients with EOCRC were compared with late-onset CRC. We also used multivariable Cox proportional hazard models to find predictors of overall survival in patients with EOCRC.

Results

The proportion of early-onset CRC was 9.1% of 518 patients with CRC, and the clinical and pathological characteristics were similar between early-onset (n = 47) and late-onset CRC (n = 134). However, EOCRC had a preponderance for distal tumor location (70.2% vs. 50.7%, P = 0.02) and T1-2 stage disease (23.4% vs. 11.2%, P = 0.04), compared with those of late-onset CRC. Using multivariable Cox proportional hazard models, only vascular invasion (hazard ratio = 8.75, 95% confidence interval 1.139‒67.197) was found to be a risk factor for overall survival (P = 0.04) for patients with CRC.

Conclusion

EOCRC had preponderance for distal tumor location and early T-stage disease, compared with late-onset CRC. Considering the increasing incidence of EOCRC, more studies on clinical and pathological characteristics of EOCRC may be warranted.

Distinct Molecular Profiles of Sporadic Early-Onset Colorectal Cancer: A Population-Based Cohort and Systematic Review

Background and Aims

The observed increase in the incidence of early-onset colorectal cancer (EOCRC) is being driven by sporadic cases, but the molecular characteristics of these tumors are not fully understood. Our objective was to investigate the prevalence of microsatellite instability (MSI) and selected mutations in sporadic EOCRC, and their association with survival.

Methods

Firstly, we compared the prevalence of molecular characteristics and survival within a population-based cohort study of 652 stage II and III colon cancer patients in Northern Ireland, comparing sporadic early-onset (<50 years, n = 35) with older (60-69 years, n = 179) patients. Secondly, a systematic review for studies reporting the prevalence of MSI, mismatch repair deficiency (dMMR), or BRAF, KRAS, NRAS, PIK3CA, and TP53 mutations in sporadic EOCRC was conducted. A meta-analysis was performed to calculate pooled estimates of the prevalence of molecular features in sporadic EOCRC.

Results

Firstly, within the cohort study, EOCRC patients did not have a significantly increased risk of colorectal cancer-specific death (adjusted hazard ratio 1.20; 95% confidence interval [CI] 0.61-2.39) compared with 60- to 69-year-olds. Second, 32 studies were included in the systematic review. The pooled analysis estimated a prevalence of 10% (95% CI 7%-14%) for MSI high/dMMR in sporadic EOCRC. BRAF and KRAS mutations had a prevalence of 1% (95% CI 0%-3%) and 32% (95% CI 23%-40%), respectively.

Conclusion

The molecular characteristics of sporadic EOCRC differ from those of cancers in older adults, particularly regarding reduced prevalence of BRAF mutations. Ten percent of sporadic EOCRC display MSI high/dMMR. Further studies are needed to address survival in sporadic EOCRC cases and whether molecular profiles influence EOCRC outcomes in this patient group.

Analysis of Septin 9 Gene Hypermethylation as Follow-Up Biomarker of Colorectal Cancer Patients after Curative Surgery

Background: The Septin 9 test analyzes the methylation status of the SEPT9 gene, which appears to be hypermethylated in patients with colorectal cancer (CRC). This has been validated as a colorectal cancer screening test. Due to the high sensitivity and specificity found, the justification was to use it as a biomarker tool for monitoring minimal residual disease after radical surgery and recurrence. Methods: A prospective study was carried out at the Fundación Jiménez Díaz University Hospital extracting peripheral blood from 28 patients and 4 healthy donors. Free circulating DNA was obtained and subsequently a PCR reaction to quantify the number of methylated genes. Samples were obtained preoperatively and postoperatively at five to seven days, one and three months after surgery. Results: A total of 32 preoperative samples were analyzed. The sensitivity of the test to detect CRC was 55.6% and specificity was 100%. There were 22 postsurgical samples obtained at 5–7 days after surgery, the sensitivity to detect tumor recurrences was 100% and specificity was 75%. There were 21 samples analyzed 1 month after surgery exhibiting a sensitivity and specificity of 100% and 94.7%, respectively. At 3 months, 31 postsurgical samples were analyzed and the sensitivity and specificity were 66.7% and 80%. Conclusions: Detection of methylation of Septin 9 gene in circulating plasma DNA, obtained from a peripheral blood sample, may be a useful, non-invasive and effective method for detecting minimal residual disease and could therefore predict CRC tumor recurrences. The optimal time in our series to obtain the best prediction results based on Septin 9 methylation levels was one month after surgery. Despite these considerable findings, a study with more patients is necessary to obtain more robust conclusions.

Gut Dysbiosis and Intestinal Barrier Dysfunction: Potential Explanation for Early-Onset Colorectal Cancer

Colorectal cancer (CRC) is a heterogeneous disease that commonly affects individuals aged more than 50 years old globally. Regular colorectal screening, which is recommended for individuals aged 50 and above, has decreased the number of cancer death toll over the years. However, CRC incidence has increased among younger population (below 50 years old). Environmental factors, such as smoking, dietary factor, urbanization, sedentary lifestyle, and obesity, may contribute to the rising trend of early-onset colorectal cancer (EOCRC) because of the lack of genetic susceptibility. Research has focused on the role of gut microbiota and its interaction with epithelial barrier genes in sporadic CRC. Population with increased consumption of grain and vegetables showed high abundance of Prevotella, which reduces the risk of CRC. Microbes, such as Fusobacterium nucleatum, Bacteroides fragilis and Escherichia coli deteriorate in the intestinal barrier, which leads to the infiltration of inflammatory mediators and chemokines. Gut dysbiosis may also occur following inflammation as clearly observed in animal model. Both gut dysbiosis pre- or post-inflammatory process may cause major alteration in the morphology and functional properties of the gut tissue and explain the pathological outcome of EOCRC. The precise mechanism of disease progression from an early stage until cancer establishment is not fully understood. We hypothesized that gut dysbiosis, which may be influenced by environmental factors, may induce changes in the genome, metabolome, and immunome that could destruct the intestinal barrier function. Also, the possible underlying inflammation may give impact microbial community leading to disruption of physical and functional role of intestinal barrier. This review explains the potential role of the interaction among host factors, gut microenvironment, and gut microbiota, which may provide an answer to EOCRC.

Comparative genomic signatures in young and old Chinese patients with colorectal cancer

BACKGROUND

Occurrence at a young age is known to be associated with unique clinical features in colorectal cancer (CRC). However, the genomic differences between young and old patients with CRC are not well elucidated and, to the best of our knowledge, have never been investigated in a Chinese population.

METHODS

Tumor tissue samples from 29 young (age ≤50 years) and 46 old (age >50 years) patients with CRC were collected. Targeted sequencing of 808 cancer-related genes was conducted to characterize the genomic landscape for Chinese CRC.

RESULTS

Overall, mutational profiles exhibited notable differences between the two groups. In particular, APC and PIK3CA mutations were more frequently observed in old patients (p = 0.009 and p = 0.012, respectively), while SMAD4 mutations tended to occur in young patients (p = 0.054). Mutation loci distributions of KRAS in the young cohort differed from those in the old cohort, and a higher frequency of KRAS codon 12 mutations was potentially associated with a young age (p = 0.076). The frequencies of clinically actionable alterations were analyzed by defined age categories, which unveiled a distinctive targeted genomic profile in the young group. Furthermore, among patients with mismatch repair-proficient (pMMR) CRC, tumor mutation burden (TMB) was positively correlated with age (Pearson's r = 0.306, p = 0.011), and genomic alterations associated with high TMB in young patients differentiated from those in old patients.

CONCLUSIONS

These findings revealed different molecular characterization between young and old Chinese patients with CRC, which may provide novel insights for the personalized treatment of CRC.

Colorectal cancer screening from 45 years of age: Thesis, antithesis and synthesis

Colorectal cancer incidence and mortality in patients younger than 50 years are increasing, but screening before the age of 50 is not offered in Europe. Advanced-stage diagnosis and mortality from colorectal cancer before 50 years of age are increasing. This is not a detection-bias effect; it is a real issue affecting the entire population. Three independent computational models indicate that screening from 45 years of age would yield a better balance of benefits and risks than the current start at 50 years of age. Experimental data support these predictions in a sex- and race-independent manner. Earlier screening is seemingly affordable, with minimal impediments to providing younger adults with colonoscopy. Indeed, the American Cancer Society has already started to recommend screening from 45 years of age in the United States. Implementing early screening is a societal and public health problem. The three independent computational models that suggested earlier screening were criticized for assuming perfect compliance. Guidelines and recommendations should be derived from well-collected and reproducible data, and not from mathematical predictions. In the era of personalized medicine, screening decisions might not be based solely on age, and sophisticated prediction software may better guide screening. Moreover, early screening might divert resources away from older individuals with greater biological risks. Finally, it is still unknown whether early colorectal cancer is part of a continuum of disease or a biologically distinct disease and, as such, it might not benefit from screening at all. The increase in early-onset colorectal cancer incidence and mortality demonstrates an obligation to take actions. Earlier screening would save lives, and starting at the age of 45 years may be a robust screening option.

Intermediate-onset colorectal cancer: A clinical and familial boundary between both early and late-onset colorectal cancer

Comparative studies of colorectal cancer (CRC) according to the age of onset have found differences between early-onset CRC (EOCRC) and late-onset CRC (LOCRC). Using this as a starting point, we wished to determine whether intermediate-onset CRC (IOCRC) might also be considered as an independent group within CRC. We performed a retrospective comparative study of the clinicopathological and familial features, as well as of the symptoms and their duration, of a total of 272 subjects diagnosed with CRC classified into three groups according to the age-of-onset (98 EOCRC, 83 IOCRC and 91 LOCRC). The results show that from a clinicopathological point of view, IOCRC shared certain features with EOCRC (gender, prognosis), and with LOCRC (multiple primary CRCs), whereas it also had characteristics that were specific for IOCRC (mean number of associated polyps). A gradual progression was observed from EOCRC to LOCRC from a greater family aggregation to sporadic cases, in parallel with a change of Lynch Syndrome cases to the sporadic microsatellite instability pathway, with the IOCRC being a boundary group that is more related to EOCRC. With respect to symptoms, duration and correlation with stages, IOCRC appeared more similar to EOCRC. Clinically, IOCRC behaves as a transitional group between EOCRC and LOCRC, with features in common with both groups, but also with IOCRC-specific features. Excluding cases with familial cancer history, the awareness for EOCRC diagnosis should be extended to IOCRC.

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.

Does cyclin E and p57kıp2 expression have prognostic and survival value in colorectal adenocarcinoma?

INTRODUCTION

Colorectal cancer is still one of the main causes of cancer death in the world. There is a continous need for novel biomarkers for diagnose, treatment modalities and follow-up. Cyclin E and p57^KIP2 as the positive and negative regulators of cell cycle seem to be an important target for investigations.

MATERIALS AND METHODS

In a retrospective setting, primary colorectal adenocarcinoma cases examined in Mustafa Kemal University, School of Medicine, Pathology Department between 2008-2015 were reviewed. Immunohistochemical expressions of cyclin E and p57^KIP2 in 80 pairs of colorectal carcinoma and adjacent normal mucosal tissues were evaluated and the findings were compared with clinicopathological parameters and survival time.

RESULTS

There were no statistically significant difference between two groups both in cyclin E and p57^KIP2 stained tissues (P>0.05). There were 40 (50%) patients in high-expression group and 40 (50%) patients in low-expression group for cyclin E. p57^KIP2 was negative in 55 (68.75%) patients and positive in 25 (31.75%) patients. There were no statistically significant relation between p57^KIP2 and cyclin E expressions with clinicopathologic parameters defined as age, gender, lymphovascular invasion, perineural invasion, depth of invasion, nodal involvement, emergency in operation, perforation before operation and overall survival except that there was significant relation between p57^KIP2 expression and histological grade (P=0.012).

CONCLUSIONS

Immunohistochemical studies of cyclin E and p57^KIP2 should be performed with larger series of patients supported by more detailed technical research methods to be candidates as predictive markers for treatment modalities and prognostic factors.

Early onset sporadic colorectal cancer: Worrisome trends and oncogenic features

Early onset colorectal cancers, defined as arising before 50 years of age, are a growing health hazard in western and eastern countries alike. The incidence of colon and rectal cancers in young individuals is projected to increase by as much as 90% and 140%, respectively, by 2030. Although several known cancer risk factors (e.g. smoking, alcohol, dietary habits) have been investigated, there is no single compelling explanation for this epidemiological trend. While some early onset colorectal cancers have been associated with germline mutations in cancer predisposition genes, genetic syndromes are implicated in only a fraction of these cancers (20%) and do not explain the rising incidence. Colorectal neoplasms develop through microsatellite instability or chromosomal instability pathways, with most of the early onset colorectal cancers exhibiting microsatellite stable phenotypes. Genome-wide hypomethylation is a feature of a subgroup of early onset cancers, which appears to be correlated with chromosomal instability and poor prognosis.

NOMO-1 gene is deleted in early-onset colorectal cancer

To characterize clinical features of a recurrent alteration in 16p13.12-p13.11 in Colorectal Cancer (CRC), mainly in Early-onset subgroup (EOCRC), and to assess the status of NOMO1, a gene located in that region, we analyzed differential clinicopathological, familial and molecular features of CRC subsets with and without alterations in the 16p13.12-p13.11, in global and EOCRC groups. We confirmed the region by fluorescence in-situ hybridization, and Quantitative Real-Time PCR analyzed the status of NOMO1 in different age-of-onset and Microsatellite Instability (MSI)-status CRC subsets. Both age-of-onset subsets were subsequently extended to further confirm NOMO1 gene changes. 16p13.12-p13.11 alterations were observed in 23.3% of CRCs, and was detected more frequently in EOCRC (33.3%) than in late-onset CRC (16.3%). The group with deletion in 16p showed a higher frequency of females and left-colon locations; a better prognosis; and higher Chromosomal Instability. Within the primary EOCRC population, 34 out of 34 of tumours showed a homozygous deletion in NOMO1, while in the late-onset population only 2 of the 17 tumours (11.7%) showed it. In the extended group, we found 61 out of 75 EOCRC patients (81.3%) with homozygous deletion and 7 patients (9.3%) with heterozygous deletion of NOMO1; moreover, in the new 50 late-onset patients, the proportions of deletions decreased. Microsatellite-Stable (MSS) EOCRC showed a very high proportion of homozygous loss of NOMO1 (54 of 59 cases, 91.5%), while the deletion was observed in only 7 out of 16 MSI cases. Deletion of NOMO1 is a molecular marker predominantly associated with EOCRC, particularly MSS subtypes.

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

Background

Since there is a predilection of some clinical and molecular features for a given tumor location, we assessed whether this can be confirmed in late-onset colorectal cancer (LOCRC).

Results

Right colon cancers showed features associated with sporadic Microsatellite Instability: predominance of female cases and BRAF mutations, and an important mucinous component. Left colon cancers developed a higher number of polyps and multiple primary CRCs, showed the strongest familial component, and had better prognosis. Rectal cancers showed a predominantly sporadic phenotype, with worse prognosis and a CpG Island Methylator Phenotype (CIMP)-High. No copy number alterations (CNAs) greater than or equal to 50% were observed in this LOCRC group, and the most recurrent alterations were losses at 5q13 and 14q11, and gains at 7q11, 7q21-q22, 19p13-p12, 19q13 and 20p11-q11. KRAS and PIK3CA were the only mutated genes showing differences according to the tumor location, mainly for right colon cancers.

Materials and Methods

We analyzed clinical and molecular characteristics of LOCRC at different tumor locations in order to determine if there are differential phenotypes related with the location in the colon.

Conclusions

Categorizing LOCRC according to tumor location appears to be an adequate first step to resolving the heterogeneity of this subset of CRC.

Findings in young adults at colonoscopy from a hospital service database audit

BACKGROUND

Colorectal cancer (CRC) diagnosed at <50 years is predominantly located in the distal colon and rectum. Little is known about which lesion subtypes may serve as CRC precursors in young adults. The aim of this work was to document the prevalence and histological subtype of lesions seen in patients aged <50 years, and any associated clinical features.

METHODS

An audit of the colonoscopy database at The Queen Elizabeth Hospital in Adelaide, South Australia over a 12-month period was undertaken. Findings were recorded from both colonoscopy reports and corresponding histological examination of excised lesions.

RESULTS

Data were extracted from colonoscopies in 2064 patients. Those aged <50 comprised 485 (24%) of the total. CRC precursor lesions (including sessile serrated adenoma/polyps (SSA/P), traditional serrated adenomas, tubular adenomas ≥10 mm or with high-grade dysplasia, and conventional adenomas with villous histology) were seen in 4.3% of patients aged <50 and 12.9% of patients aged ≥50 (P <0.001). Among colonoscopies yielding CRC precursor lesions in patients under 50 years, SSA/P occurred in 52% of procedures (11/21), compared with 27% (55/204) of procedures in patients aged 50 and older (P = 0.02). SSA/P were proximally located in (10/11) 90% of patients aged under 50, and 80% (43/54) of those aged 50 and older (P = 0.46).

CONCLUSIONS

SSA/P were the most frequently observed CRC precursor lesions in patients aged <50. Most CRCs in this age group are known to arise in the distal colon and rectum suggesting that lesions other than SSA/P may serve as the precursor for the majority of early-onset CRC.

Different clinical characteristics in sporadic young-age onset colorectal cancer

The incidence of colorectal cancer (CRC) is increasing in young-age patients, but the clinical history is not established. Authors analyzed the clinical characteristics of young-age onset CRC to support basic information for setting treatment policies.Between January 2006 to January 2014, 100 CRC patients diagnosed at the age of 10 to 39 were analyzed. The clinicopathologic characteristics were reviewed based on medical records. Survival outcomes including overall survival (OS), disease-free survival (DFS), and progression-free survival (PFS) were analyzed. This study was conducted as a retrospective, observation study.Among 100 patients, 86 patients were diagnosed as CRC at their thirties. Seventy-nine patients had no familial history of cancer. At initial diagnosis, 59 patients showed the normal CEA level (≤3 ng/mL), and 61 patients were diagnosed as advanced CRC (40% stage III, 21% stage IV). Sixty-four patients had lower location-sigmoid colon, rectosigmoid junction, or rectum. Recurrence rate was 7.9% in stage I to III CRC. Although median OS was not reached, patients with normal CEA level showed better survival outcome (P = 0.013) and patients with perineural invasion showed poorer survival (P = 0.011). The 5-year survival rate of total patient population was estimated as 75%. However, median OS of stage IV patients were 19 months (range 7.9-60.63 months), shorter than historical data of >24 months.Young-age CRC was most commonly diagnosed at their thirties, with no familial history, normal range of CEA and located below sigmoid colon. In young-age onset stage IV CRC, patients showed inferior OS compared to historical data. Based on our data, different surveillance program other than serum CEA level (e.g., sigmoidoscopy) is needed in young-age patient population.

Frequent BRAF mutation in early-onset colorectal cancer in Taiwan: association with distinct clinicopathological and molecular features and poor clinical outcome

BACKGROUND

Occurrence of early-onset colorectal cancer (EOCRC) under the age of 30 is very rare and the molecular characteristics are poorly understood. A low BRAF mutation rate has been noted in several studies of EOCRC from Western countries.

AIMS

To determine the clinicopathological and molecular features of EOCRCs in Taiwan.

METHODS

KRAS/BRAF gene mutation, mismatch repair protein immunohistochemistry, microsatellite instability and CpG island methylation phenotype analyses were examined to determine the molecular characteristics of EOCRC.

RESULTS

Sixty-six patients with EOCRC at our hospital between 2000 and 2012 were studied. BRAF mutation was detected in 11 of the 59 tumours analysed (19%) and the rate was significantly higher than the overall BRAF mutation rate of colorectal cancer in patients older than 30 years (p<0.001). Clinically, 9 of 11 patients with BRAF-mutated tumours presented with advanced-stage diseases and they presented significantly more frequently with stage IV disease than those with BRAF wild-type tumours (p=0.042). Histologically, BRAF mutation was associated with a poorly differentiated histology, a serrated precursor polyp and focal signet ring cell differentiation (p=0.042, 0.008 and 0.008, respectively). None of the BRAF-mutated tumours was mismatch repair protein-deficient and/or microsatellite instability-high. Overall survival of patients with BRAF-mutated tumours was significantly worse than that of patients with BRAF wild-type tumours, despite adjustment for the disease stages and tumour differentiation.

CONCLUSIONS

BRAF mutation was frequent in EOCRCs in Taiwan and was associated with distinct clinicopathological and molecular features.

Classifying early-onset colorectal cancer according to tumor location: new potential subcategories to explore

Early-onset Colorectal Cancer (ECRC) represents a significant and increasing proportion of Colorectal Cancer (CRC), but it is a heterogeneous entity that probably encompasses specific subclasses. On the premise that the carcinogenetic mechanism and progression of CRC may differ with location, we analyzed molecular and clinical characteristics of ECRC according to tumor location in order to identify more homogeneous subgroups of CRC. Right-sided ECRC is a subset in which most Lynch Syndrome cases are found, with earlier stages at diagnosis and better prognosis. At this location the CpG Island Methylator Phenotype (CIMP) is predominant and Chromosomal Instability (CI) is rare. Left-sided ECRC appears as a transitional or intermediate location, except for CI tumors, that seem to predominate at this location. Finally, rectal ECRC shows Microsatellite Stability, CIMP low-0 and low CI - with recurrent altered chromosomal regions in common with left-sided ECRC-, possibly in relation with Microsatellite And Chromosomal Stable tumors, but with an unexpected familial component and worse prognosis. All this suggest that the molecular basis of ECRC varies with tumor location, which could affect the clinical management of patients.

The association of age and race and the risk of large bowel polyps

BACKGROUND

Blacks have a higher incidence of colorectal cancer and a younger age at diagnosis compared with whites. Few studies have investigated racial differences in risk of metachronous adenomas and serrated polyps and whether this risk differs by polyp characteristics or age of patient.

METHODS

We analyzed data pooled from three placebo-controlled adenoma chemoprevention trials to explore racial differences in the risk of large bowel polyps in patients ≤50 and >50 years of age. Using generalized linear regression, we estimated risk ratios (RR) and 95% confidence intervals (CI) as measures of the association between race and risk of one or more adenomas or serrated polyps after randomization.

RESULTS

Among the 2,605 subjects who completed at least one follow-up exam, blacks ≤50 years of age had a higher risk of any conventional adenoma (RR, 1.70; 95% CI, 0.99-2.92) and advanced neoplasms (RR, 4.05; 95% CI, 1.43-11.46) and a nonsignificantly lower risk of serrated polyps (RR, 0.75; 95% CI, 0.34-1.62) compared with whites. Among patients >50 years, there was no racial difference in risk of adenomas (RR, 1.08; 95% CI, 0.92-1.27) or advanced neoplasms (RR, 1.05; 95% CI, 0.71- 1.56). However, blacks had a significantly lower risk of serrated polyps (RR, 0.65; 95% CI, 0.49-0.87) than whites.

CONCLUSIONS

Our results demonstrate a higher risk of metachronous adenomas in blacks compared with whites at younger ages.

IMPACT

Our results suggest that the racial disparity in colorectal cancer incidence may be due to an excess of neoplasia in younger blacks.

Diagnostic and prognostic significance of different mucin expression, preoperative CEA, and CA-125 in colorectal carcinoma: A clinicopathological study

Background:

Colorectal carcinoma (CRC) is the fourth most commonly diagnosed malignant disease worldwide, with over 1 million new cases and approximately 5,00,000 deaths each year.

Aims and Objectives:

This prospective observational study was done to study the clinicopathological characteristics of CRC including mucin stains and correlate the preoperative serum carcinoembryonic antigen (CEA) and cancer antigen (CA)-125 levels with the prognosis.

Materials and Methods:

A total of 90 CRCs were included from December 2010 to June 2013. Detailed history and relevant clinical/radiological findings were noted in all clinically and/or radiologically suspected cases of CRC. Preoperative blood samples were collected for serum CEA and CA-125 level estimation. The mucin expression was evaluated with special stains.

Results:

The combined Alcian blue-periodic acid Schiff (PAS) staining was positive for both stains in 68.88% cases indicating that both neutral and acidic mucins are increased in CRC. High preoperative serum CEA levels were seen in 82.22% cases, whereas preoperative serum CA-125 levels showed an increase in 20% cases. Higher levels of these tumor markers corresponded with higher TNM stage.

Conclusions:

Mucin evaluation in CRCs remains one of the valuable methods as mucinous variants correlate with worse prognosis. Preoperative serum CEA level assessment is an indispensible adjunct to the diagnosis and prognosis of CRC. However, preoperative serum CA-125 level measurement is not an efficient tool for prognostication in CRC and should not be recommended for routine use.

Sporadic early-onset colorectal cancer is a specific sub-type of cancer: a morphological, molecular and genetics study

Sporadic early onset colorectal carcinoma (EOCRC) which has by definition no identified hereditary predisposition is a growing problem that remains poorly understood. Molecular analysis could improve identification of distinct sub-types of colorectal cancers (CRC) with therapeutic implications and thus can help establish that sporadic EOCRC is a distinct entity. From 954 patients resected for CRC at our institution, 98 patients were selected. Patients aged 45–60 years were excluded to help define “young” and “old” groups. Thirty-nine cases of sporadic EOCRC (patients≤45 years with microsatellite stable tumors) were compared to both microsatellite stable tumors from older patients (36 cases, patients>60 years) and to groups of patients with microsatellite instability. Each group was tested for TP53, KRAS, BRAF, PIK3CA mutations and the presence of a methylator phenotype. Gene expression profiles were also used for pathway analysis. Compared to microsatellite stable CRC from old patients, sporadic EOCRC were characterized by distal location, frequent synchronous metastases and infrequent synchronous adenomas but did not have specific morphological characteristics. A familial history of CRC was more common in sporadic EOCRC patients despite a lack of identified hereditary conditions (p = 0.013). Genetic studies also showed the absence of BRAF mutations (p = 0.022) and the methylator phenotype (p = 0.005) in sporadic EOCRC compared to older patients. Gene expression analysis implicated key pathways such as Wnt/beta catenin, MAP Kinase, growth factor signaling (EGFR, HGF, PDGF) and the TNFR1 pathway in sporadic EOCRC. Wnt/beta catenin signaling activation was confirmed by aberrant nuclear beta catenin immunostaining (p = 0.01). This study strongly suggests that sporadic EOCRC is a distinct clinico-molecular entity presenting as a distal and aggressive disease associated with chromosome instability. Furthermore, several signaling pathways including the TNFR1 pathway have been identified as potential biomarkers for both the diagnosis and treatment of this disease.

Early-onset colorectal cancer patients without family history are "at very low risk" for lynch syndrome

Introduction

Several studies evaluated the prevalence of Lynch Syndrome (LS) in young onset colorectal cancer (CRC) patients and the results were extremely variable (5%-20%). Immunohistochemistry (IHC) for MMR proteins and/or MSI analysis are screening tests that are done, either by themselves or in conjunction, on colon cancer tissue to identify individuals at risk for LS. The primary aim of our study was to evaluate the prevalence of LS in a large series of early-onset CRC without family history compared with those with family history. The secondary aim was to assess the diagnostic accuracy of IHC and MSI analysis as pre-screening tools for LS.

Methods

Early-onset CRC patients (≤ 50 years) were prospectively recruited in the study. IHC and MSI analysis were performed in all the patients. Germ-line mutation analysis (GMA) was carried out in all MMR deficient tumors. A logistic regression model was performed to identify clinical features predictive of MSI-H.

Results

117 early onset CRC cases were categorized in three groups (A, B, C) according with family history of CRC. IHC and MSI analysis showed MMR deficiency in 6/70 patients (8.6%) of group A, 24/40 patients (60%) of group B and none of group C. GMA showed a deleterious mutation in 19 (47.5%) patients of group B. MSI analysis had a diagnostic accuracy of 95.7% (CI 92.1-99.4) and IHC of 83.8% (CI 77.1-90.4). The logistic regression model revealed that by using a combination of the two features “No Amsterdam Criteria” and ”left sided CRC” to exclude MSI-H, accuracy was 89.7% (84.2-95.2).

Conclusions

Early-onset CRC patients, with left sided CRC and without family history are “at very low risk” for Lynch syndrome. The two simple criteria of family history and CRC site could be used as a pre-screening tool to evaluate whether or not patients should undergo tissue molecular screening. In the few cases of suspected LS (right sided CRC and/or Amsterdam Criteria), a reasonable approach could be to perform MSI analysis first and IHC afterwards only in MSI-H patients.

Recognizing hereditary colorectal cancer

Colorectal cancer is the second-leading cause of cancer death in the United States. About 25% of patients have a personal or family history that suggests a hereditary colorectal cancer syndrome. This article describes the clinical and pathological characteristics of hereditary colorectal cancer, appropriate screening tests, and when to refer patients to a genetic counselor.

Microsatellite instability status affects gene expression profiles in early onset colorectal cancer patients

BACKGROUND

The association between microsatellite instability (MSI) status and gene expression profiles in the early onset sporadic colorectal cancer (CRC) has not been clearly established. The aim of this study was to identify the altered gene expression patterns depending on the MSI status of early onset CRC and determine specific biomarkers that could provide novel therapeutic molecular targets in the Turkish population.

MATERIALS AND METHODS

MSI markers (BAT25, BAT26, D2S123, D5S346, and D17S250) were investigated in tumors from 36 early onset sporadic CRC patients in whom gene expression profiles were analyzed previously. The relationship between the gene expression profiles depending on MSI status was evaluated.

RESULTS

A total of 15 tumors (16.66%) were identified as having MSI and 21 tumors (58.33%) were identified as having microsatellite stability (MSS). CK20 and MAP3K8 upregulation, observed in MSS tumors, was significantly associated with lymph node metastasis, recurrence, and/or distant metastasis and a short median survival (P < 0.05). REG1A upregulation is also correlated with recurrence and/or distant metastasis and a short median survival in patients with MSI tumors (P < 0.05).

CONCLUSIONS

High expression levels of CK20 and MAP3K8 in MSS tumors and REG1A in MSI tumors correlated with a poor prognosis in CRC patients. Further studies and validations are required; these genes may provide novel therapeutic molecular targets for the development of anticancer drugs related to MSI status for early onset CRC treatment.

Exome sequencing in diagnostic evaluation of colorectal cancer predisposition in young patients

OBJECTIVE

Early-onset colorectal cancer (CRC), defined here as age of onset less than 40 years, develops frequently in genetically predisposed individuals. Next-generation sequencing is an increasingly available option in the diagnostic workup of suspected hereditary susceptibility, but little is known about the practical feasibility and additional diagnostic yield of the technology in this patient group.

MATERIALS AND METHODS

We analyzed 38 young CRC patients derived from a set of 1514 CRC cases. All 38 tumors had been tested in our laboratory for microsatellite instability (MSI), and Sanger sequencing had been used to screen for MLH1 and MSH2 mutations in MSI cases. Also, gastrointestinal polyposis had been diagnosed clinically and molecularly. Family histories were acquired from national registries. If inherited syndromes had not been diagnosed in routine diagnostic efforts (n = 23), normal tissue DNA was analyzed for mutations in a comprehensive set of high-penetrance genes (MLH1, MSH2, MSH6, PMS2, APC, MUTYH, SMAD4, BMPR1A, LKB1/STK11, and PTEN) by exome sequencing.

RESULTS

CRC predisposition syndromes were confirmed in 42% (16/38) of early-onset CRC patients. Hereditary nonpolyposis colorectal cancer was diagnosed in 12 (32%) patients, familial adenomatous polyposis in three (7.9%), and juvenile polyposis in one (2.6%) patient. Exome sequencing revealed one additional MLH1 mutation. Over half of the patients had advanced cancers (Dukes C or D, 61%, 23/38). The majority of nonsyndromic patients had unaffected first-degree relatives and microsatellite-stable tumors.

CONCLUSIONS

Microsatellite instability positivity or gastrointestinal polyposis characterized all patients with unambiguous highly penetrant germline mutations. In our series, exome sequencing produced little added value in diagnosing the underlying predisposition conditions.

Factors influencing quality of bowel preparation for colonoscopy

Recent technological advances in colonoscopy have led to improvements in both image enhancement and procedural performance. However, the utility of these technological advancements remain dependent on the quality of bowel preparation during colonoscopy. Poor bowel preparation has been shown to be associated with lower quality indicators of colonoscopy performance, such as reduced cecal intubation rates, increased patient discomfort and lower adenoma detection. The most popular bowel preparation regimes currently used are based on either Polyethylene glycol-electrolyte, a non-absorbable solution, or aqueous sodium phosphate, a low-volume hyperosmotic solution. Statements from various international societies and several reviews have suggested that the efficacy of bowel preparation regimes based on both purgatives are similar, although patients’ compliance with these regimes may differ somewhat. Many studies have now shown that factors other than the type of bowel preparation regime used, can influence the quality of bowel preparation among adult patients undergoing colonoscopy. These factors can be broadly categorized as either patient-related or procedure-related. Studies from both Asia and the West have identified patient-related factors such as an increased age, male gender, presence of co-morbidity and socio-economic status of patients to be associated with poor bowel preparation among adults undergoing routine out-patient colonoscopy. Additionally, procedure-related factors such as adherence to bowel preparation instructions, timing of bowel purgative administration and appointment waiting times for colonoscopy are recognized to influence the quality of colon cleansing. Knowledge of these factors should aid clinicians in modifying bowel preparation regimes accordingly, such that the quality of colonoscopy performance and delivery of service to patients can be optimised.

Racial disparities in advanced-stage colorectal cancer survival

PURPOSE

African-Americans (AA) have a higher incidence of and lower survival from colorectal cancer (CRC) compared with European Americans (EA). In the present study, statewide, population-based data from South Carolina Central Cancer Registry are used to investigate the relationship between race and age on advanced-stage CRC survival.

METHODS

The study population was comprised of 3,865 advanced pathologically documented colon and rectal adenocarcinoma cases diagnosed between 01 January 1996 and 31 December 2006: 2,673 (69 %) EA and 1,192 (31 %) AA. Kaplan-Meier methods were used to generate median survival time and corresponding 95 % confidence intervals (CI) by race, age, and gender. Factors associated with survival were evaluated by fitting Cox proportional hazards regression models to generate hazard ratios (HR) and 95 % CI.

RESULTS

We observed a significant interaction between race and age on CRC survival (p = 0.04). Among younger patients (<50 years), AA race was associated with a 1.34 times (95 % CI 1.06-1.71) higher risk of death compared with EA. Among older patients, we observed a modest increase in risk of death among AA men compared with EA [HR 1.16 (95 % CI 1.01-1.32)] but no difference by race between women [HR 0.94 (95 % CI 0.82-1.08)]. Moreover, we observed that the disparity in survival has worsened over the past 15 years.

CONCLUSIONS

Future studies that integrate clinical, molecular, and treatment-related data are needed for advancing understanding of the racial disparity in CRC survival, especially for those <50 years old.

Expression analysis of B-Raf oncogene in V600E-negative benign and malignant tumors of the thyroid gland: correlation with late disease onset

B-Raf, a member of the Raf serine/threonine kinase family, is an intermediate molecule in the mitogen-activated protein kinase pathway, which relays extracellular signals from the cell membrane to the nucleus via a cascade of phosphorylation events, ultimately promoting cancer development. This pathway is usually activated in human neoplasias. The purpose of this study was to investigate the role of B-Raf in thyroid pathology. We scanned for the presence of mutations at codon 600 (V → E) of the B-Raf gene, using a PCR-RFLP assay. In tumors with no mutation (32 benign and malignant thyroid tumors) and in their adjacent normal tissue, we measured the expression levels of B-Raf gene, using a quantitative real-time PCR (qPCR) assay. B-Raf expression in V600E-negative tumors deviated from the normal pattern, since it was overexpressed in 42 % of benign samples and downregulated in 54 % of malignant specimens. Hashimoto's thyroiditis also seemed to play an important role, since benign specimens with Hashimoto's thyroiditis had a 2.2-fold higher B-Raf expression than samples without thyroiditis (1.71 ± 0.63 vs. 0.78 ± 0.13). Statistical analysis revealed that B-Raf deregulation postponed disease onset by more than 10 years in both benign and malignant thyroid (benign: 55.6 ± 3.9 vs. 45.3 ± 3.3, p = 0.049; malignant: 52.2 ± 3.5 vs. 33.0 ± 7.9, p = 0.020). From the above results, we deduce that in the absence of mutation activation, B-Raf overexpression or downregulation is a protective event, since it delays the development of both malignant and benign thyroid tumors.

Evidence for possible non-canonical pathway(s) driven early-onset colorectal cancer in India

Two genetic instability pathways viz. chromosomal instability, driven primarily by APC mutation induced deregulated Wnt signaling, and microsatellite instability (MSI) caused by mismatch repair (MMR) inactivation, together account for >90% of late-onset colorectal cancer (CRC). Our understanding of early-onset sporadic CRC is however comparatively limited. In addition, most seminal studies have been performed in the western population and analyses of tumorigenesis pathway(s) causing CRC in developing nations have been rare. We performed a comparative analysis of early and late-onset CRC from India with respect to common genetic aberrations including Wnt, KRAS, and p53 (constituting the classical CRC progression sequence) in addition to MSI. Our results revealed the absence of Wnt and MSI in a significant proportion of early-onset as against late-onset CRC in India. In addition, KRAS mutation frequency was significantly lower in early-onset CRC indicating that a significant proportion of CRC in India may follow tumorigenesis pathways distinct from the classical CRC progression sequence. Our study has therefore revealed the possible existence of non-canonical tumorigenesis pathways in early-onset CRC in India.

Expression of cyclin E in stage III colorectal carcinoma

Carcinogenesis is characterized by an abnormal regulation of the cell cycle. Regulators of the cell cycle such as cyclin E play an important role in neoplasia and may be correlated with prognosis. The clinical significance of the expression of cyclin E in stage III colorectal carcinoma has not yet been investigated. The expression of cyclin E was evaluated in 49 patients. Using a multivariate analysis, the expression of cyclin E in the tumor at diagnosis was compared with various clinicopathological variables, including age, gender, tumor site, tumor size, tumor differentiation and lymph node involvement. There were more node-positive cases in the cyclin E-negative group than in the cyclin E-positive group (P=0.003). However, there was no correlation between the degree of cyclin E expression and the clinical data. In conclusion, our data suggest that overexpression of cyclin E does not predict the clinical outcome in colorectal cancer stage III. Negative cyclin E staining may be associated with lymph node involvement.

Influence of anatomical subsite on the incidence of microsatellite instability, and KRAS and BRAF mutation rates in patients with colon carcinoma

There is a growing amount of data supporting the concept that cancers originating from the proximal and distal colon are distinct clinicopathological entities. The incidence of MSI and BRAF mutation is strongly associated with right sided tumor location, whereas there are conflicting results for KRAS mutation rates. However, to date, no data exist whether and to what extent defined colonic subsites influence MSI status, KRAS and BRAF mutation rates. We selected primary colon cancer from 171 patients operated on at our institution between 2007 and 2010. BRAF, KRAS mutation rates and microsatellite instability were determined and correlated with clinicopathological features and tumor location. MSI-h cancers were significantly associated with poor histological grade but a lower rate of distant metastases. KRAS-mutated tumors were linked to lower T-stage and better differentiation. Colon carcinomas with BRAF mutation were significantly associated with distant metastatic spread and poor histological grade. Furthermore, we found that MSI-h status, KRAS and BRAF mutation rates varied remarkably among the colonic subsites irrespective of right- and left-sided origin, respectively. The results of the current study provide further evidence that a simple classification into right- and left-sided colon carcinoma does not represent the complexity of this tumor entity.

Colorectal cancer linkage on chromosomes 4q21, 8q13, 12q24, and 15q22

A substantial proportion of familial colorectal cancer (CRC) is not a consequence of known susceptibility loci, such as mismatch repair (MMR) genes, supporting the existence of additional loci. To identify novel CRC loci, we conducted a genome-wide linkage scan in 356 white families with no evidence of defective MMR (i.e., no loss of tumor expression of MMR proteins, no microsatellite instability (MSI)-high tumors, or no evidence of linkage to MMR genes). Families were ascertained via the Colon Cancer Family Registry multi-site NCI-supported consortium (Colon CFR), the City of Hope Comprehensive Cancer Center, and Memorial University of Newfoundland. A total of 1,612 individuals (average 5.0 per family including 2.2 affected) were genotyped using genome-wide single nucleotide polymorphism linkage arrays; parametric and non-parametric linkage analysis used MERLIN in a priori-defined family groups. Five lod scores greater than 3.0 were observed assuming heterogeneity. The greatest were among families with mean age of diagnosis less than 50 years at 4q21.1 (dominant HLOD = 4.51, α = 0.84, 145.40 cM, rs10518142) and among all families at 12q24.32 (dominant HLOD = 3.60, α = 0.48, 285.15 cM, rs952093). Among families with four or more affected individuals and among clinic-based families, a common peak was observed at 15q22.31 (101.40 cM, rs1477798; dominant HLOD = 3.07, α = 0.29; dominant HLOD = 3.03, α = 0.32, respectively). Analysis of families with only two affected individuals yielded a peak at 8q13.2 (recessive HLOD = 3.02, α = 0.51, 132.52 cM, rs1319036). These previously unreported linkage peaks demonstrate the continued utility of family-based data in complex traits and suggest that new CRC risk alleles remain to be elucidated.

Early-onset colorectal cancer is an easy and effective tool to identify retrospectively Lynch syndrome

BACKGROUND AND OBJECTIVES

Early age of onset is a marker of a possible hereditary component in colorectal cancer (CRC). We evaluated whether early age of onset is a good marker to identify Lynch syndrome, especially retrospectively, and if there is any other feature that could improve this identification.

METHODS

We selected patients with CRC aged 45 years or younger from the pathological reports of three different institutions and different periods of time. Clinical information, family history, and tumor samples were obtained. Cases were classified according to mismatch repair (MMR) proficiency.

RESULTS

Of 133 tumors, 22 showed microsatellite instability (MSI). In 15 MSI cases, a germline mutation in 1 of the MMR genes was identified, 7 of which were not identified before. The positive predictive value (PPV) of right colon CRC for a positive genetic MMR test is 30.6%, whereas "signet ring" cells and fulfillment Amsterdam II criteria have PPVs of 42.9% and 47.8%, respectively. Combining right-sided CRC with mucin production, with fulfilling Amsterdam II criteria, or with "signet ring" cells, PPVs are 54.5, 64.3, and 100%. The probability of the absence of a mutation when CRC is located in the left colon is 94.7%, whereas absence of aggregation for Lynch-related neoplasm has a 100% probability.

CONCLUSIONS

Early age of onset is an effective method to identify retrospectively Lynch syndrome. Taking into account the location and histology features of the tumor, and the familial history of the cases, we notably increase the a priori probability of detecting a germline MMR mutation.