Association of colorectal adenoma with other malignancies in Swedish families

Genetic analyses supporting colorectal, gastric, and prostate cancer syndromes

Colorectal cancer (CRC), prostate cancer (PrC), and gastric cancer (GC) are common worldwide, and the incidence is to a certain extent dependent on genetics. We have recently shown that in families with more than one case of CRC, the risk of other malignancies is increased. We therefore suggested the presence of not yet described CRC syndromes. In this study, we have searched for genetic susceptibility loci for potential cancer syndromes involving CRC combined with PrC and/or GC. We have performed SNP (single-nucleotide polymorphism)-based linkage analyses in 45 families with CRC, PrC, and GC. In the regions with suggested linkage, we performed exome and association haplotype analyses. Five loci generated a high logarithm of odds (HLOD) score >2, suggestive of linkage, in chromosome bands 1q31-32, 1q24-25, 6q25-26, 18p11-q11, and Xp11. Exome analysis detected no potential pathogenic sequence variants. The haplotype association study showed that one of the top five haplotypes with the lowest P value in the chromosome band 6q25 interestingly was found in the family which contributed the most to the increased HLOD at that locus. This study supports a suggested hereditary cancer syndrome involving CRC and PrC and indicates a location at 6q25. The impact of this locus needs to be confirmed in additional studies.

Prostate cancer patients may have an increased risk of coexisting advanced colorectal neoplasms

Background/aims

Patients being treated for prostate cancer (PCa) have an increased risk of developing colorectal cancer. However, whether PCa patients are inherently at a higher risk of colorectal neoplasms (CRNs) is unknown. We aimed to investigate the risk of CRNs in PCa patients.

Materials and methods

Patients who had been diagnosed with PCa at a tertiary medical center and had colonoscopy within 1 year of the PCa diagnosis were investigated. Patients were propensity-matched 1:2 by age and body mass index to asymptomatic control subjects who had undergone colonoscopy for routine health screening. CRN was defined as histological confirmation of an adenoma or adenocarcinoma component. Advanced CRN was defined as any of the following: 1) histological findings of high-grade dysplasia, 2) inclusion of villous features, 3) tumor ≥1 cm in size, or 4) presence of an adenocarcinoma. Risk factors for CRN and advanced CRN were evaluated by univariate and multivariate analysis.

Results

A total of 191 patients diagnosed with PCa had colonoscopies within 1 year of PCa diagnosis. Of these, 23 patients with a history of previous malignancy and seven with incomplete colonoscopies were excluded, leaving 161 patients in the PCa group. Although presence of PCa was not a significant risk factor for CRN by multivariate analysis, PCa was a significant risk factor for advanced CRN (odds ratio [OR] 3.300; 95% confidence interval [CI] 1.766–6.167; P<0.001). Other significant risk factors for advanced CRN were age (OR 1.050; 95% CI 1.003–1.009; P=0.036) and body mass index (OR 1.205; 95% CI 1.067–1.361; P=0.003), whereas aspirin use (OR 0.414; 95% CI 0.173–0.990; P=0.047) was a preventive factor.

Conclusion

The risk of advanced CRN may be significantly increased in patients with PCa. Patients with PCa should have a colonoscopy at the time of PCa diagnosis.

Common genetic variant on BMP4 contributes to colorectal adenoma and cancer: A meta-analysis based on 15 studies

Epidemiological studies indicate a genetic contribution to colorectal cancer (CRC), but specific genetic variants remain unknown. Genome-wide association studies have identified rs4444235 at BMP4 as a new colorectal cancer (CRC) and colorectal adenoma (CRA) susceptibility locus in populations of European descent. After that, several validation studies have been conducted among various ethnic populations to investigate if the SNP was associated with CRC/CRA, but the results have been inconsistent. To investigate this inconsistency and derive a more precise estimation of the relationship, a meta-analysis involving 54,631 CRC cases, 3995 CRA cases and 88,098 controls from 15 studies was performed. Potential sources of heterogeneity including ethnicity, sample size, study design and endpoint were also assessed. Overall, the summary OR of CRC was 1.06 (95% CI: 1.04-1.08, P<10(-5)). In the subgroup analysis by ethnicity, significantly increased risks were found in East Asians (OR=1.07, 95% CI: 1.01-1.12, P=0.01) and Caucasians (OR=1.07, 95% CI: 1.05-1.10, P<10(-5)); while no significant associations were found among African Americans and other ethnic populations in all genetic models. In addition, significant associations were also detected for CRA with per-allele OR of 1.09 (95% CI: 1.03-1.14, P=0.001). Our findings demonstrated that BMP4-rs4444235 is a risk factor associated with increased CRC and CRA susceptibility, but these associations vary in different ethnic populations.

Common genetic variants (rs4779584 and rs10318) at 15q13.3 contributes to colorectal adenoma and colorectal cancer susceptibility: evidence based on 22 studies

Several genome-wide association studies on colorectal cancer (CRC) have reported similar findings of a new susceptibility locus, 15q13.3. After that, a number of studies have reported that the rs4779584 and rs10318 polymorphisms at chromosome 15q13.3 have been implicated in CRC and colorectal adenoma (CRA) risk; however, these studies have yielded inconsistent results. To investigate this inconsistency, we performed a meta-analysis of 22 studies involving a total of 48,468 CRC cases, 4,189 CRA cases, and 85,105 controls for the two polymorphisms to evaluate its effect on genetic susceptibility for CRC/CRA. Potential sources of heterogeneity and publication bias were also systematically explored. Overall, the summary odds ratio (OR) of rs4779584-T variant for CRC was 1.13 (95 % CI 1.09-1.16, P < 10(-5)) and 1.15 (95 % CI 1.04-1.28, P = 0.006) for CRA. After stratified by ethnicity, significantly increased CRC risks were found for rs4779584 polymorphism among East Asians and Caucasians, while no significant associations were detected among African American and other ethnic populations. A meta-analysis of studies on the rs10318 polymorphism also showed significant overall association with CRC, yielding a per-allele OR of 1.13 (95 % CI 1.02-1.24, P = 0.02). In the subgroup analysis by ethnicity, significantly increased CRC risks were found in Caucasians; whereas no significant associations were found among East Asians and African Americans. This meta-analysis demonstrated that the rs4779584 and rs10318 polymorphism at 15q13.3 is a risk factor associated with increased CRC/CRA susceptibility, but these associations vary in different ethnic populations.

Much of the genetic risk of colorectal cancer is likely to be mediated through susceptibility to adenomas

Several single-nucleotide polymorphisms (SNPs) have been associated with colorectal cancer (CRC) susceptibility. Most CRCs arise from adenomas, and SNPs therefore might affect predisposition to CRC by increasing adenoma risk. We found that 8 of 18 known CRC-associated SNPs (rs10936599, rs6983267, rs10795668, rs3802842, rs4444235, rs1957636, rs4939827, and rs961253) were over-represented in CRC-free patients with adenomas, compared with controls. Ten other CRC-associated SNPs (rs6691170, rs6687758, rs16892766, rs7136702, rs11169552, rs4779584, rs9929218, rs10411210, rs4813802, and rs4925386) were not associated significantly with adenoma risk. Genetic susceptibility to CRC in the general population is likely to be mediated in part by predisposition to adenomas.

Multiple primary cancers among colorectal cancer survivors in Queensland, Australia, 1996-2007

PURPOSE

To quantify the demographic and clinical factors associated with an increased risk of multiple primary cancers (MPCs) among colorectal cancer survivors.

METHODS

Standardized incidence ratios for MPCs were calculated for residents of Queensland, Australia, who were diagnosed with a first primary colorectal cancer between 1996 and 2005 and survived for at least 2 months. Relative risk ratios were calculated for all MPCs combined and selected individual sites using multivariate Poisson models.

RESULTS

A total of 1,615 MPCs were observed among 15,755 study patients. The cohort had a significant excess risk of developing subsequent colorectal (SIR = 1.47, 95 % CI 1.30-1.66) or non-colorectal (SIR = 1.24, 95 % CI 1.18-1.31) cancers relative to the incidence of cancer in the general population. Age at initial diagnosis, follow-up time, initial colorectal subsite, and surgical treatment were independently associated (p < 0.01) with the overall risk of developing MPCs after adjustment. The relative risk ratio was 1.23 (95 % CI 1.07-1.41) for those aged 20-59 years compared with the 70-79 age group and 0.82 (95 % CI 0.72-0.92) for 1-5-year follow-up relative to the first year. The likelihood of being diagnosed with a MPC was 33 % higher (95 % CI 1.12-1.56) for surgically treated patients and 45 % higher (95 % CI 1.29-1.64) after proximal colon cancers relative to rectal cancer.

CONCLUSIONS

While these population-based results do not incorporate all possible risk factors, they form an important foundation from which to further investigate the etiological causes that result in the development of MPCs among colorectal cancer survivors.