Phenotypic and molecular characteristics of hyperplastic polyposis

Colorectal polyps increase the glycolytic activity

In colorectal cancer (CRC) energy metabolism research, the precancerous stage of polyp has remained rather unexplored. By now, it has been shown that CRC has not fully obtained the glycolytic phenotype proposed by O. Warburg and rather depends on mitochondrial respiration. However, the pattern of metabolic adaptations during tumorigenesis is still unknown. Understanding the interplay between genetic and metabolic changes that initiate tumor development could provide biomarkers for diagnosing cancer early and targets for new cancer therapeutics. We used human CRC and polyp tissue material and performed high-resolution respirometry and qRT-PCR to detect changes on molecular and functional level with the goal of generally describing metabolic reprogramming during CRC development. Colon polyps were found to have a more glycolytic bioenergetic phenotype than tumors and normal tissues. This was supported by a greater GLUT1, HK, LDHA, and MCT expression. Despite the increased glycolytic activity, cells in polyps were still able to maintain a highly functional OXPHOS system. The mechanisms of OXPHOS regulation and the preferred substrates are currently unclear and would require further investigation. During polyp formation, intracellular energy transfer pathways become rearranged mainly by increasing the expression of mitochondrial adenylate kinase (AK) and creatine kinase (CK) isoforms. Decreased glycolysis and maintenance of OXPHOS activity, together with the downregulation of the CK system and the most common AK isoforms (AK1 and AK2), seem to play a relevant role in CRC development.

From Mixed Hyperplastic/Adenomatous Polyp to Sessile Serrated Lesion: A Long and Winding Road for Long and Winding Crypts

CONTEXT.—

During the past 3 decades, numerous articles in the literature have offered terminology, diagnostic criteria, and consensus recommendations regarding the entity currently referred to by the World Health Organization as sessile serrated lesion. Given the many names and various, variably reproducible diagnostic criteria ascribed to sessile serrated lesion, confusion persists for many pathologists and gastroenterologists regarding the diagnosis. This distinction is important, as sessile serrated lesion can progress to malignancy, unlike its main differential diagnosis, hyperplastic polyp. Research studies have shed light on the characteristic architecture and morphology, immunohistochemical patterns, and molecular alterations of sessile serrated lesion, and multiple consensus meetings around the globe have developed their criteria and nomenclature, often clashing or mixing terms.

OBJECTIVE.—

To provide a narrative review from the entity's early description to our current understanding.

DATA SOURCES.—

The existing scientific and clinical literature, published texts, medical society recommendations, and specialty consensus guidelines.

CONCLUSIONS.—

The current World Health Organization criteria are a distillation of this scientific process, but terminology is still a point of contention worldwide.

Small RNA sequencing of sessile serrated polyps identifies microRNA profile associated with colon cancer

Sessile serrated adenoma/polyps (SSA/Ps) of the colon account for 20-30% of all colon cancers. Small non-coding RNAs, including microRNAs (miRNAs), may function as oncogenes or tumor suppressor genes involved in cancer development. Small RNA sequencing (RNA-seq) was used to characterize miRNA profiles in SSA/Ps, hyperplastic polyps (HPs), adenomatous polyps and paired uninvolved colon. Our 108 small RNA-seq samples' results were compared to small RNA-seq data from 212 colon cancers from the Cancer Genome Atlas. Twenty-three and six miRNAs were differentially expressed in SSA/Ps compared to paired uninvolved colon and HPs, respectively. Differential expression of MIR31-5p, MIR135B-5p and MIR378A-5p was confirmed by RT-qPCR. SSA/P-specific miRNAs are similarly expressed in colon cancers containing genomic aberrations described in serrated cancers. Correlation of miRNA expression with consensus molecular subtypes suggests more than one subtype is associated with the serrated neoplasia pathway. Canonical pathway analysis suggests many of these miRNAs target growth factor signaling pathways.

The 9p21 locus as a potential therapeutic target and prognostic marker in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related-death worldwide. Despite extensive efforts to identify valid biomarkers for the risk stratification of CRC patients, there are few of proven clinical utility. It is recognized that genetic factors play a major role in determining susceptibility to CRC. Recent genome-wide association studies have demonstrated common genetic variants in a region on chromosome 9p21 associated with an increased risk of CRC. Several genetic polymorphisms have been identified in this region that are associated with CRC. Three genes are located at this locus; CDKN2B(encoding-p15ink4b), CDKN2A (encoding-p16ink4a/p14ARF) and 3′ end of CDKN2BAS (termed-antisense-noncoding-RNA in the INK4-locus [ANRIL]). ANRIL has a post-transcriptional modulatory activity, which has been shown to perturb the expression of nearby genes. It also plays an important role in coordinating tissue remodeling through regulation of cell proliferation, apoptosis, aging, extra-cellular matrix remodeling and inflammatory response. However, the role of ANRIL is not well understood in CRC. Hypermethylation of the p14ARF and p16INK4a genes is often found in some tumors, including CRC. However, further studies are necessary to explore the clinical utility of these putative markers in risk stratification, and in the assessment of prognosis. In this review, we have summarized the prognostic and therapeutic potential of the p14ARF and p16INK4a genes in patients with colorectal cancer.

MUTYH-associated colon disease: Adenomatous polyposis is only one of the possible phenotypes. A family report and literature review

Aims and background

The MutY human homologue gene (MUTYH) is responsible for about a quarter of attenuated familial adenomatous polyposis. Occasionally, it has been associated with hyperplastic polyps and serrated adenoma. We report a family where the same MUTYH mutation determined four different phenotypes, including a case of hyperplastic polyposis syndrome.

Patients and methods

A family with a history of right-sided colon cancer and multiple colonic polyposis was investigated. Genetic tests were correlated with clinical findings to define phenotypic manifestations of MUTYH mutations. The pertinent English-language literature was reviewed to evaluate the risk of malignancy of MUTYH and the role of prophylactic surgery.

Results

Three male siblings carried a biallelic MUTYH mutation (G382D-exon13), while the fourth was heterozygote. One developed an isolated cecal cancer at the age of 48. Another, aged 38, was diagnosed with numerous minute colonic and rectal polyps and underwent a proctocolectomy, with final pathology showing a picture of hyperplastic and lymphoid polyposis. The third biallelic brother, 46 years old, developed four hyperplastic lesions, while the heterozygote brother had a large flat serrated adenoma of the right colon removed at the age of 50.

Conclusion

Many aspects of MUTYH mutation still need to be clarified and one of them regards the different phenotypic expressions. Although the majority of reported cases manifested attenuated adenomatous polyposis, hyperplastic polyps and serrated adenomas appear to be more common than expected. Presenting hyperplastic polyposis syndrome is very unusual and may represent a clinical dilemma for correct management. Current evidence suggests to handle MUTYH-associated polyposis as typical FAP.

Colorectal cancer risk factors in patients with serrated polyposis syndrome: a large multicentre study

OBJECTIVE

Serrated polyposis syndrome (SPS) is associated with an increased colorectal cancer (CRC) risk, although the magnitude of the risk remains uncertain. Whereas intensive endoscopic surveillance for CRC prevention is advised, predictors that identify patients who have high CRC risk remain unknown. We performed a multicentre nationwide study aimed at describing the CRC risk in patients with SPS and identifying clinicopathological predictors independently associated with CRC.

DESIGN

From March 2013 through September 2014, patients with SPS were retrospectively recruited at 18 Spanish centres. Data were collected from medical, endoscopy and histopathology reports. Multivariate logistic regression was performed to identify CRC risk factors.

RESULTS

In 296 patients with SPS with a median follow-up time of 45 months (IQR 26-79.7), a median of 26 (IQR 18.2-40.7) serrated polyps and 3 (IQR 1-6) adenomas per patient were detected. Forty-seven patients (15.8%) developed CRC at a mean age of 53.9±12.8, and 4 out of 47 (8.5%) tumours were detected during surveillance (cumulative CRC incidence 1.9%). Patients with >2 sessile serrated adenomas/polyps (SSA/Ps) proximal to splenic flexure and ≥1 proximal SSA/P with high-grade dysplasia were independent CRC risk factors (incremental OR=2, 95% CI 1.22 to 3.24, p=0.006). Patients with no risk factors showed a 55% decrease in CRC risk (OR=0.45, 95% CI 0.24 to 0.86, p=0.01).

CONCLUSIONS

Patients with SPS have an increased risk of CRC, although lower than previously published. Close colonoscopy surveillance in experienced centres show a low risk of developing CRC (1.9% in 5 years). Specific polyp features (SSA/P histology, proximal location and presence of high-grade dysplasia) should be used to guide clinical management.

Gene Signature in Sessile Serrated Polyps Identifies Colon Cancer Subtype

Sessile serrated colon adenoma/polyps (SSA/P) are found during routine screening colonoscopy and may account for 20% to 30% of colon cancers. However, differentiating SSA/Ps from hyperplastic polyps (HP) with little risk of cancer is challenging and complementary molecular markers are needed. In addition, the molecular mechanisms of colon cancer development from SSA/Ps are poorly understood. RNA sequencing (RNA-Seq) was performed on 21 SSA/Ps, 10 HPs, 10 adenomas, 21 uninvolved colon, and 20 control colon specimens. Differential expression and leave-one-out cross-validation methods were used to define a unique gene signature of SSA/Ps. Our SSA/P gene signature was evaluated in colon cancer RNA-Seq data from The Cancer Genome Atlas (TCGA) to identify a subtype of colon cancers that may develop from SSA/Ps. A total of 1,422 differentially expressed genes were found in SSA/Ps relative to controls. Serrated polyposis syndrome (n = 12) and sporadic SSA/Ps (n = 9) exhibited almost complete (96%) gene overlap. A 51-gene panel in SSA/P showed similar expression in a subset of TCGA colon cancers with high microsatellite instability. A smaller 7-gene panel showed high sensitivity and specificity in identifying BRAF-mutant, CpG island methylator phenotype high, and MLH1-silenced colon cancers. We describe a unique gene signature in SSA/Ps that identifies a subset of colon cancers likely to develop through the serrated pathway. These gene panels may be utilized for improved differentiation of SSA/Ps from HPs and provide insights into novel molecular pathways altered in colon cancer arising from the serrated pathway. Cancer Prev Res; 9(6); 456-65. ©2016 AACR.

Role of MYH polymorphisms in sporadic colorectal cancer in China: a case-control, population-based study

PURPOSE

Biallelic germline variants of the 8-hydroxyguanine (8-OG) repair gene MYH have been associated with colorectal neoplasms that display somatic G:C?T:A transversions. However, the effect of single germline variants has not been widely studied, prompting the present investigation of monoallelic MYH variants and susceptibility to sporadic colorectal cancer (CRC) in a Chinese population.

PATIENTS AND METHODS

Between January 2006 and December 2012, 400 cases of sporadic CRC and 600 age- and sex-matched normal blood donors were screened randomly for 7 potentially pathogenic germline MYH exons using genetic testing technology. Variants of heterozygosity at the MYH locus were assessed in both sporadic cancer patients and healthy controls. Univariate and multivariate analyses were performed to determine risk factors for cancer onset.

RESULTS

Five monoallelic single nucleotide polymorphisms (SNPs) were identified in the 7 exon regions of MYH, which were detected in 75 (18.75%) of 400 CRC patients as well as 42 (7%) of 600 normal controls. The region of exon 1 proved to be a linked polymorphic region for the first time, a triple linked variant including exon 1-316 G?A, exon 1-292 G?A and intron 1+11 C?T, being identified in 13 CRC patients and 2 normal blood donors. A variant of base replacement, intron 10-2 A?G, was identified in the exon 10 region in 21 cases and 7 controls, while a similar type of variant in the exon 13 region, intron 13+12 C?T, was identified in 8 cases and 6 controls. Not the only but a newly missense variant in the present study, p. V463E (Exon 14+74 T?A), was identified in exon 14 in 6 patients and 1 normal control. In exon 16, nt. 1678-80 del GTT with loss of heterozygosity (LOH) was identified in 27 CRC cases and 26 controls. There was no Y165C in exon 7 or G382D in exon 14, the hot- spot variants which have been reported most frequently in Caucasian studies. After univariate analysis and multivariate analysis, the linked variant in exon 1 region (p=0.002), intron 10-2 A?G (p=0.004) and p. V463E (p=0.036) in the MYH gene were selected as 3 independent risk factors for CRC.

CONCLUSIONS

According to these results, the linked variant in Exon 1 region, Intron 10-2 A?G of base replacement and p. V463E of missense variant, the 3 heterozygosity variants of MYH gene in a Chinese population, may relate to the susceptibility to sporadic CRC. Lack of the hot-spot variants of Caucasians in the present study may due to the ethnic difference in MYH gene.

Prevalence of serrated polyposis syndrome and its association with synchronous advanced adenoma and lifestyle

We assessed the clinicopathological characteristics of patients with serrated polyposis syndrome (SPS) and the incidence of advanced adenoma/colorectal cancer (CRC). We prospectively enrolled 249 consecutive patients who underwent colonoscopy at the National Cancer Center Hospital over a 6-month period. All the polyps were diagnosed using magnification colonoscopy and resection/biopsy. The enrolled patients were divided into two groups, i) those with ≥5 histologically diagnosed hyperplastic polyps (HPs) proximal to the sigmoid colon, with at least 2 polyps >10 mm in diameter and ii) those with ≥20 HPs distributed throughout the colon. The clinical characteristics of the two groups were compared, including lifestyle, family history of CRC and colonoscopic findings. HPs were identified in 228 patients, of whom 21 (8.4%) had SPS. All 21 patients had ≥20 HPs distributed throughout the colon, with none having >2 HPs ≥1 cm in diameter in the right colon. Synchronous advanced adenoma/CRC was diagnosed in 76/249 (30.5%) patients. The prevalence of advanced adenoma/CRC was higher among patients with compared to those without SPS (P=0.075). SPS was also associated with older age and higher body mass index (BMI). Our results suggested that older age and higher BMI are independent risk factors for SPS. Advanced adenoma/CRC tended to occur more frequently among patients with compared to those without SPS, although the difference was not statistically significant.

Serrated polyposis syndrome

SUMMARY 

Serrated polyposis syndrome, also called hyperplastic polyposis, is a condition characterized by numerous neoplastic polyps throughout the colon and rectum. The polyps possess a distinct serrated morphology. The term serrated refers to the ‘saw-tooth’ pattern formed by epithelial cells in the colonic crypts on standard histologic preparations. Historically, serrated lesions have been lumped together under the term ‘hyperplastic polyps’, and were assumed to carry no malignant potential. Over the past decade, however, an increasing body of evidence suggests that serrated lesions exist along a spectrum and represent an alternative molecular pathway to the development of colorectal cancer in contrast to the traditional adenocarcinoma sequence. Although a hallmark genetic signature for serrated polyposis syndrome remains unidentified, this is an area of active investigation.

Incidence of colonic neoplasia in patients with serrated polyposis syndrome who undergo annual endoscopic surveillance

BACKGROUND & AIMS

Patients with serrated polyposis syndrome (SPS) are advised to undergo endoscopic surveillance for early detection of polyps and prevention of colorectal cancer (CRC). The optimal surveillance and treatment regimen is unknown. We performed a prospective study to evaluate a standardized endoscopic treatment protocol in a large cohort of patients with SPS.

METHODS

We followed a cohort of patients with SPS who received annual endoscopic surveillance at the Academic Medical Centre in Amsterdam, The Netherlands from January 2007 through December 2012. All patients underwent clearing colonoscopy with removal of all polyps ≥3 mm. After clearance, subsequent follow-up colonoscopies were scheduled annually. The primary outcomes measure was the incidence of CRC and polyps. Secondary outcomes were the incidence of complications and the rate of preventive surgery.

RESULTS

Successful endoscopic clearance of all polyps ≥3 mm was achieved in 41 of 50 (82%) patients. During subsequent annual surveillance, with a median follow-up time of 3.1 years (interquartile range, 1.5-4.3 years), CRC was not detected. The cumulative risks of detecting CRC, advanced adenomas, or large (≥10 mm) serrated polyps after 3 surveillance colonoscopies were 0%, 9%, 34%, respectively. Twelve patients (24%) were referred for preventive surgery; 9 at initial colonoscopy and 3 during surveillance. Perforations or severe bleeding did not occur.

CONCLUSIONS

Annual surveillance with complete removal of all polyps ≥3 mm with timely referral of selected high-risk patients for prophylactic surgery prevents development of CRC in SPS patients without significant morbidity. Considering the substantial risk of polyp recurrence, close endoscopic surveillance in SPS seems warranted. www.trialregister.nl ID NTR2757.

Familial colorectal cancer, beyond Lynch syndrome

Although 30% of individuals diagnosed with colorectal cancer (CRC) report a family history of the disease, only 5% to 6% carry germline mutations in genes associated with known hereditary cancer syndromes. The evaluation and management of families affected with CRC can be complicated by variability in disease phenotypes and limited sensitivity of genetic tests. In this review, we examine what is currently known about familial CRC and what we have yet to learn, and explore how novel genomic approaches might be used to identify additional genetic and epigenetic factors implicated in heritable risk for cancer.

What clinicians wish to know about benign colorectal polyps: an operative classification

INTRODUCTION

In recent years we assisted to a real "boom" of colorectal polyps, mainly due to the diffusion of screening procedures and of colonoscopy. This new "Polyp Epidemic" raises a series of problems and challenges. It became clear that many syndromes are defined by the number, histological type and location of polyps, together with extraintestinal manifestations and, in most cases, specific molecular changes. This paper discusses some of the above mentioned points, focusing on the relative role of endoscopists and pathologists. The objective is to reach an operative classification of the most common polyps observed in daily practice which might be of help for the identification of inherited syndromes.

METHODS AND RESULTS

Six main histological types of polyps are defined and underlined: Adenoma, hyperplastic/serrated, hamartoma, ganglioneuroma, mixed, inflammatory. The importance of a brief description, in pathology reports, of each type of polyps is fundamental for a correct diagnosis. Each of the defined polyps is associated with inherited syndromes whose genetic basis has recently been elucidated. Relevant information should be given, and separated from additional (and not strictly necessary) information.

RECOMMENDATIONS

A correct polyp analysis is a valuable element for identifying specific inherited syndromes. Polyps represent a precious tool for planning screening and follow-up in a given individual. In addition, these lesions focus the interest of clinicians toward syndrome which were considered as rare diseases; indeed, the explosion of molecular biology and the diffusion of colonoscopy revealed that these conditions are frequent and amenable of treatment.

Hereditary colorectal cancer syndromes

SUMMARY Colorectal cancer (CRC) is one of the most common malignancies and the second-leading cause of cancer death in both sexes in developed countries. Over the last 25 years, highly penetrant monogenic germline mutations that predispose to CRC and other digestive tumors have been identified, accounting for up to 5% of all CRC cases. Identification and characterization of these disorders have allowed modification of their natural history, with a substantial decrease in morbidity and mortality among high-risk patients. Recognizing hereditary CRC has also impacted predictive genetic testing and personalized medicine based on genomic information. This review summarizes the current knowledge on hereditary CRC regarding pathogenesis, clinical features, diagnostic evaluation and management recommendations.

Serrated polyposis: colonic phenotype, extracolonic features, and familial risk in a large cohort

BACKGROUND

Serrated polyposis is a poorly understood and likely underdiagnosed condition. Little is known regarding the colorectal cancer risk, extracolonic phenotype, and cause of serrated polyposis.

OBJECTIVE

The aim of this study is to describe the clinical and family history features of a large cohort of individuals with serrated polyposis.

DESIGN

This is a retrospective cohort study from 2 prospectively collected registries.

PATIENTS

Patients meeting the updated 2010 World Health Organization criteria for serrated polyposis were included.

MAIN OUTCOME MEASURES

We report descriptive statistics for clinical and family history factors.

RESULTS

A total of 52 individuals met criteria for serrated polyposis. Of these, one had Lynch syndrome and was not included in the statistical analyses. Median age at serrated polyposis diagnosis was 51 years (range, 18-77). Twenty-four (47%) patients were male, and 25 (49%) had a history of smoking. Two hundred sixty-eight lower endoscopic procedures were performed; 42 (82%) patients had colorectal adenomas, 8 (16%) had a personal history of colorectal cancer (only 1 was diagnosed during follow-up), 12 (24%) had extracolonic tumors (4 had more than 1 primary tumor), and 19 (37%) reported a family history of colorectal cancer. Esophagogastroduodenoscopy in 30 individuals revealed only 1 (3%) with unexplained gastroduodenal polyps. No association was found between colorectal cancer diagnosis and sex, age at serrated polyposis diagnosis, extracolonic tumor, history of adenoma, or smoking status.

LIMITATIONS

This was a retrospective study with no comparison groups.

CONCLUSIONS

Gastroduodenal polyps are uncommon and likely not associated with serrated polyposis. Although extracolonic tumors were common in our cohort, it is still unclear whether these are associated with serrated polyposis. Our data, along with previous studies, support an association between serrated polyposis and smoking. Further work is still needed to clarify the effect of smoking on polyp development/progression in serrated polyposis.

Clinicopathologic features of hyperplastic/serrated polyposis syndrome in Japan

BACKGROUND AND AIM

Hyperplastic/serrated polyposis syndrome (HPS) is a condition characterized by multiple hyperplastic/serrated colorectal polyps. The risk of colorectal cancer (CRC) is increased in HPS. The clinicopathologic characteristics of HPS in Japanese patients are unknown. The aim of this study is to clarify the clinicopathologic features of HPS in Japanese patients.

METHODS

We retrieved records of patients diagnosed with HPS between April 2008 and March 2011 from the endoscopy database of Hiroshima University Hospital. In addition, we mailed a questionnaire to the hospital's 13 affiliated hospitals in July 2012. Data collected from the database and questionnaires included patient age, sex, number of hyperplastic/serrated polyps and tubular adenomas, size of the largest polyp, polyp location, resection for polyps, coexistence of HPS with CRC, and the diagnostic criterion met.

RESULTS

Of the 73,608 patients who underwent colonoscopy, 10 (0.014%) met the criteria for HPS. The mean age of these patients was 58.3 years, and 6 (60%) were men. No subjects had a first-degree relative with HPS. Four (40%) HPS patients had more than 30 hyperplastic/serrated polyps, and average size of the largest polyp was 19 mm. Three (30%) HPS patients had coexistence of HPS with CRC. In these 3 patients, polyps were observed throughout the colorectum.

CONCLUSIONS

Although HPS was a rare condition in the overall study population, patients with the disease may have high risk of CRC. HPS should be diagnosed correctly and followed up carefully.

Phenotypic characterization and familial risk in hyperplastic polyposis syndrome

BACKGROUND. Hyperplastic polyposis syndrome (HPS) is a rare condition characterized by numerous hyperplastic polyps (HP) with a pancolonic distribution. Genetic and environmental factors, including smoking, may be responsible for phenotypic differences. OBJECTIVE. To characterize HPS patients' phenotype and to determine HPS risk and colorectal cancer (CRC) risk in the first-degree relatives (FDRs). PATIENTS AND METHODS. Eight HPS patients were followed at our Gastroenterology Department (2008-2012). The data included (1) macroscopic and histological analysis of polyps, (2) demographic information about patients and their families and (3) colonoscopy results of FDR that accepted a screening exam. RESULTS. Six of the eight index cases (ICs) had family history of CRC. Of the 24 FDRs screened, 5 were diagnosed with HPS. In our study, HPS and CRC prevalence in FDR was 625 and 9 times higher than the risk of the general population. Polyps over 10 mm were preferentially located in proximal colon (p < 0.001). Advanced polyps were larger (p < 0.001) than HP and more frequent in older patients (p = 0.0054). Nonsmokers had smaller polyps (p = 0.037) preferentially in the proximal colon (p = 0.04) and a lower age at HPS diagnosis. Patients with CRC family history manifest HPS at an earlier age and patients whose relatives had CRC before 50 years had larger polyps (p = 0.0475). Smokers with CRC family history had larger polyps than nonsmokers (p = 0.048). CONCLUSION. Despite the small sample, the results reflect the phenotypic heterogeneity of HPS as well as the increased family risk of HPS and CRC. This study points out that CRC family history and smoking influence HPS expression.

Sessile serrated adenomas in the proximal colon are likely to be flat, large and occur in smokers

AIM

To examine the epidemiology and the morphology of the proximal sessile serrated adenomas (SSAs).

METHODS

We conducted a retrospective study to identify patients with SSAs using a university-based hospital pathology database query from January 2007 to April 2011. Data collected included: age, gender, ethnicity, body mass index, diabetes, smoking, family history of colorectal cancer, aspirin, and statin use. We collected data on morphology of SSAs including site (proximal or distal), size, and endoscopic appearance (flat or protuberant). We also compared proximal SSAs to proximal tubular adenomas detected during same time period.

RESULTS

One hundred and twenty patients with SSAs were identified: 61% were distal and 39% were proximal SSAs. Proximal SSAs were more likely to be flat than distal (100% vs 78% respectively; P = 0.0001). Proximal SSAs were more likely to occur in smokers (OR = 2.63; 95%CI: 1.17-5.90; P = 0.02) and in patients with family history of colorectal cancer (OR = 4.72; 95%CI: 1.43-15.55; P = 0.01) compared to distal. Proximal SSAs were statistically more likely to be ≥ 6 mm in size (OR = 2.94; P = 0.008), and also more likely to be large (≥ 1 cm) (OR = 4.55; P = 0.0005) compared to the distal lesions. Smokers were more likely to have proximal (P = 0.02), flat (P = 0.01) and large (P = 0.007) SSAs compared to non-smokers. Compared to proximal tubular adenomas, proximal SSAs were more likely to be large and occur in smokers.

CONCLUSION

Proximal SSAs which accounted for two-fifths of all SSAs were more likely to present as flat lesions, larger SSAs, and were more likely to occur in smokers and in patients with family history of colorectal cancer. Our data has implications for colorectal cancer screening.

Serrated colon polyps as precursors to colorectal cancer

Identification of the serrated neoplasia pathway has improved our understanding of the pathogenesis of colorectal cancer (CRC). Insights include an increased recognition of the malignant potential of different types of serrated polyps such as sessile and traditional serrated adenomas. Sessile serrated adenomas share molecular features with colon tumors that have microsatellite instability and a methylator phenotype, indicating that these lesions are precursors that progress via the serrated neoplasia pathway. These data have important implications for clinical practice and CRC prevention, because hyperplastic polyps were previously regarded as having no malignant potential. There is also evidence that the serrated pathway contributes to interval or missed cancers. Endoscopic detection of serrated polyps is a challenge because they are often inconspicuous with indistinct margins and are frequently covered by adherent mucus. It is important for gastroenterologists to recognize the subtle endoscopic features of serrated polyps to facilitate their detection and removal, and thereby ensure a high-quality colonoscopic examination. Recognition of the role of serrated polyps in colon carcinogenesis has led to the inclusion of these lesions in postpolypectomy surveillance guidelines. However, an enhanced effort is needed to identify and completely remove serrated adenomas, with the goal of increasing the effectiveness of colonoscopy to reduce CRC incidence.

Clinical subtypes and molecular characteristics of serrated polyposis syndrome

BACKGROUND & AIMS

We investigated clinical and molecular differences between the different phenotypes of serrated polyposis syndrome (SPS) and the frequency of mutations in BRAF or KRAS in polyps from patients with SPS.

METHODS

We collected data on clinical and demographic characteristics of 50 patients who fulfilled the criteria for SPS. Polymerase chain reaction and sequence analysis were used to identify BRAF and KRAS mutations in 432 polyps collected from 37 patients; we analyzed CpG island methylator phenotypes in 272 of these polyps.

RESULTS

Fifteen patients (30%) had type 1 SPS and 35 had type 2 SPS. There were no significant differences in age at diagnosis, sex, smoking frequency, body mass index, or colorectal cancer predisposition between groups of patients, or in the pathologic or molecular characteristics of their polyps. A familial history of colorectal cancer or colonic polyps was reported more frequently by patients with type 2 SPS. BRAF mutations were found in 63% of polyps and KRAS mutations were found in 9.9%; 43.4% of polyps had the CpG island methylator phenotype-high phenotype. A per-patient analysis revealed that all patients had a BRAF or KRAS mutation in more than 25% of their polyps; 84.8% of patients had a mutation in BRAF or KRAS in more than 50% of their polyps.

CONCLUSIONS

Except for a greater likelihood of familial history of colorectal cancer or colonic polyps in patients with type 2 SPS, we found no significant demographic, pathologic, or molecular differences between types 1 and 2 SPS. All patients had a BRAF or KRAS mutation in at least 25% of their polyps.

Expression of olfactomedin 4 and claudin-18 in serrated neoplasia of the colorectum: a characteristic pattern is associated with sessile serrated lesion

AIMS

Olfactomedin 4 is a useful marker for stem cells in the intestine and is an independent prognostic molecule for survival in patients with colorectal cancer (CRC). Claudin-18, a component of tight junctions, correlates with poor survival in patients with CRC and is associated with the gastric phenotype. We investigated the possible usefulness of these molecules in serrated neoplasia of the colorectum.

METHODS AND RESULTS

We performed immunohistochemical analysis of colorectal polyps, including hyperplastic polyps (HP), sessile serrated lesions (SSL), traditional serrated adenomas (TSA) and conventional adenomas (CA). We also investigated the association between expression of these molecules and clinicopathological parameters in serrated adenocarcinoma (SAC) and non-SAC of the colorectum. Olfactomedin 4 expression was not detected or was decreased in SSL compared with the other polyp types. Claudin-18 expression was higher in SSL than in the other types. Similarly, positivity for olfactomedin 4 in SAC was significantly lower than that in non-SAC, and positivity for claudin-18 in SAC was significantly higher than that in non-SAC. Furthermore, claudin-18-positive SAC showed more advanced N grade and stage than claudin-18-negative SAC.

CONCLUSIONS

Reduced expression of olfactomedin 4 and ectopic expression of claudin-18 might be useful markers in the differential diagnosis of serrated polyps.

Serrated polyposis: prospective study of first-degree relatives

INTRODUCTION

Serrated polyposis (SP) is an infrequent colorectal cancer (CRC) predisposition syndrome. An unidentified genetic defect is believed to play a role in this condition. The risk of SP and/or CRC for first-degree relatives (FDRs) is not yet well known. The aim of our study was to determine the incidence of both SP and/or CRC by studying the FDRs of our index SP cases and to propose an appropriate interval for colonoscopy surveillance in this group.

METHODS

From 2005 to December 2011, we prospectively included all patients from our hospital who fulfilled the SP diagnostic criteria. We interviewed FDRs face to face and offered a colonoscopy to those who were 35 years old or older. The study was carried out with conventional and high-definition colonoscopes and chromoendoscopy with indigo carmine at the discretion of a single endoscopist. The samples were assessed by two pathologists. We reviewed the clinical data for CRC diagnosed previously in FDRs.

RESULTS

From 2005, we collected all the new cases of SP and offered a colonoscopy to 95 FDRs of 34 pedigrees. We performed colonoscopies on 78 FDRs (82.1%). The incidence of SP in the FDRs was 32% (25 patients). Seventy-six percent of patients were diagnosed with SP as they had any number of serrated polyps proximal to the sigmoid colon. Only one patient was diagnosed with CRC as a result of the screening colonoscopy. 44.1% of our index cases had an FDR with a diagnosis of CRC.

CONCLUSION

Our series, which is the largest prospective cohort of FDRs published, reports an elevated incidence of SP in FDRs, thus supporting the need for screening colonoscopy in FDR and its inclusion in the guidelines.

[Genetics of colorectal cancer]

Colorectal cancer (CRC) is one of the most frequent neoplasms in developed countries and up to 5% of all cases occur in the context of a hereditary syndrome. These hereditary forms often require a high index of suspicion for their diagnosis and specific and specialized management. Moreover, a diagnosis of hereditary CRC has major consequences not only for the patient--for whom there are highly effective preventive measures--but also for the patient's relatives, who may carry the same condition. The most significant advances in the field of hereditary CRC have been produced in the diagnosis and characterization of Lynch's syndrome and serrated polyposis syndrome.

Aberrant methylation of the PTCH1 gene promoter region in aberrant crypt foci

Patched homolog 1 (PTCH1) is a known tumor suppressor that regulates the Hedgehog (Hh) pathway and has been implicated in tumorigenesis. The role of PTCH1 in colon carcinogenesis, however, is controversial. The aim of the present study was to investigate epigenetic modifications of PTCH1 in aberrant crypt foci (ACF), the earliest precursor lesion of colorectal cancer (CRC). Using laser-capture microdissection (LCM), a pure population of ACF epithelial cells was isolated and studied. The inherent protein expression levels of SHH, PTCH1, SMO and GLI1 were assessed by immunohistochemistry for 405 ACF, including 54 dysplastic ACF (d-ACF) and 351 non-dysplastic ACF (n-ACF). The mRNA levels and methylation status of PTCH1 were also determined in 54 d-ACF and 96 n-ACF. Our data showed that the expression of SHH, SMO and GLI1 was significantly up-regulated in d-ACF, compared to n-ACF. Also, the mRNA and protein levels of PTCH1 were lower in d-ACF than n-ACF. Using MSP or MS-HRM, PTCH1 methylation was present in 64.8% (35/54) or 63.3% (34/54), respectively, of d-ACF and 19.8% (19/96) or 22.9% (11/48), respectively, of n-ACF. PTCH1 methylation was more frequent in d-ACF than n-ACF (p < 0.001) and was associated with PTCH1 mRNA levels (r = 0.358, p < 0.01). There was a statistically significant correlation between PTCH1 methylation status and the prevalence of colorectal neoplasms. In conclusion, this study suggests that aberrant methylation of the PTCH1 promoter may be an early, initiating event of colon carcinogenesis.

Serrated polyposis is an underdiagnosed and unclear syndrome: the surgical pathologist has a role in improving detection

Serrated polyposis syndrome (SPS) is poorly defined and patients have an increased but unspecified risk for colorectal carcinoma through the serrated pathway. Despite this association SPS remains relatively obscure and is therefore likely underrecognized. We determined the frequency of SPS among patients with any serrated polyps (SPs) over a 6-month "index" period, and in doing so we assessed the ability of surgical pathologists to improve SPS detection. Particular attention was given to the index procedure to assess the potential predictive value of the findings resulting from a single colonoscopy. A total of 929 patients with at least 1 SP were identified, 17 of whom (1.8%) were determined to meet World Health Organization criteria for SPS. Nine patients met the first criterion (≥ 5 proximal SPs, 2 of which are > 10 mm); 4 met the third criterion (> 20 SPs of any size distributed throughout the colon); and 4 met both criteria. Although no specific SP size or number at the index procedure was clearly superior in its ability to predict SPS, > 50% of cases would be detected if a cutoff of ≥ 3 SPs or a single SP ≥ 15 mm at the index procedure is used. In summary, SPS is rare but more likely underdiagnosed. Additional studies to address the underlying genetic basis for SPS are ongoing in order to shed further light on this syndrome. Surgical pathologists are in a unique position to assist in this endeavor by identifying those patients who either meet or seem to be at high risk of meeting World Health Organization criteria.

Serrated lesions of the colorectum: review and recommendations from an expert panel

Serrated lesions of the colorectum are the precursors of perhaps one-third of colorectal cancers (CRCs). Cancers arising in serrated lesions are usually in the proximal colon, and account for a disproportionate fraction of cancer identified after colonoscopy. We sought to provide guidance for the clinical management of serrated colorectal lesions based on current evidence and expert opinion regarding definitions, classification, and significance of serrated lesions. A consensus conference was held over 2 days reviewing the topic of serrated lesions from the perspectives of histology, molecular biology, epidemiology, clinical aspects, and serrated polyposis. Serrated lesions should be classified pathologically according to the World Health Organization criteria as hyperplastic polyp, sessile serrated adenoma/polyp (SSA/P) with or without cytological dysplasia, or traditional serrated adenoma (TSA). SSA/P and TSA are premalignant lesions, but SSA/P is the principal serrated precursor of CRCs. Serrated lesions have a distinct endoscopic appearance, and several lines of evidence suggest that on average they are more difficult to detect than conventional adenomatous polyps. Effective colonoscopy requires an endoscopist trained in the endoscopic appearance of serrated lesions. We recommend that all serrated lesions proximal to the sigmoid colon and all serrated lesions in the rectosigmoid > 5 mm in size, be completely removed. Recommendations are made for post-polypectomy surveillance of serrated lesions and for surveillance of serrated polyposis patients and their relatives.

Failure to recognize serrated polyposis syndrome in a cohort with large sessile colorectal polyps

BACKGROUND

Serrated polyposis syndrome (SPS) is a rare condition of multiple serrated colorectal polyps and cancers. Colorectal cancer risk is increased in SPS.

OBJECTIVE

We determined the prevalence of SPS in a cohort of patients with large (≥ 2 cm) sessile colorectal polyps and the rate at which the diagnosis was made by the clinicians.

DESIGN

Review of patient care database. The 2010 World Health Organization (WHO) criteria were used to identify cases of SPS.

SETTING

Tertiary academic center.

PATIENTS

529 consecutive patients referred for endoscopic resection of a sessile colorectal polyp ≥ 2 cm.

MAIN OUTCOME MEASUREMENTS

Prevalence of SPS in the cohort and frequency with which the referring physician and the endoscopist recognized SPS.

RESULTS

Of the 529 patients, 20 (4%) met the WHO criteria for SPS. Only 1 of these cases was suspected by a referring physician. Twelve cases (60%) were either diagnosed or suspected by the endoscopist at our center. Compared with all other patients without SPS, those with SPS were more likely to have an index lesion (the lesion that led to referral) that was serrated (60% vs 3.8%), to have a cecal or ascending colon index lesion (70% vs 45%), and to be current smokers (42% vs 15%). Including the first colonoscopy to remove the index lesion and 26 follow-up colonoscopies, the endoscopist at our center removed 183 serrated polyps from the 20 patients with SPS; of those polyps, 68 were >1 cm. Three patients were referred for surgical resection of involved colon. Eighteen of the 20 patients with SPS met the WHO criterion of 5 serrated polyps proximal to the sigmoid, of which 2 are >1 cm. Failure to recognize SPS by the referring physician was at least partly related to unrecognized serrated lesions. Failure to recognize SPS by the endoscopist at our institution was the result of not systematically applying WHO criteria to the polyp findings.

LIMITATIONS

Retrospective study.

CONCLUSIONS

SPS was common in a cohort of patients with large sessile colorectal polyps, and it was frequently unrecognized. These data suggest the need for better detection of serrated lesions, better awareness of SPS, and more consistent application of SPS criteria to the polyp findings of individual patients.

Serrated polyposis: the last (or only the latest?) frontier of familial polyposis?

Serrated polyps are thought to be precursors of ~15% of colorectal cancers and clinical criteria for a serrated polyposis (SP) syndrome have been proposed. In this issue of American Journal of Gastroenterology, Win et al. report that family members of individuals who meet the clinical criteria for SP are at increased risk for colorectal and possibly pancreatic cancer. The important data presented by Win et al. strongly support the concept that familial SP exists and help define the patterns of risk in this syndrome. The paper also illustrates the difficulties of trying to define a genetic syndrome on the basis of largely retrospective clinical data and highlights the importance of efforts to define the genetic basis of familial SP and to study these families in a systematic, prospective manner.

Hyperplastic Polyposis Syndrome Identified with a BRAF Mutation

Hyperplastic polyposis syndrome (HPS) is a rare condition characterized by the presence of numerous hyperplastic polyps (HPs) in the colon and rectum. Patients with HPS have an increased risk of colorectal cancer. This link is associated with gene mutations, especially B type Raf kinase (BRAF). However, a case of HPS associated with gene mutations has seldom been reported in Korea. Here, we describe a case of HPS in which a BRAF mutation was present in a 34-year-old woman. She had more than 110 HPs in the stomach and colorectum, which we removed. All of the polyps were diagnosed histologically as HPs, and no adenomatous or malignant changes were noted. We performed a BRAF and K-ras mutation analysis as well as a microsatellite analysis on the resected colon polyps. BRAF mutations were found in the resected colon polyps, but there was no evidence of K-RAS mutation or microsatellite instability.

[Gastrointestinal oncology: the genetics of colorectal cancer]

Colorectal cancer (CRC) is one of the most common malignancies in developed countries, and up to 5% of all cases occur in the context of a hereditary syndrome. These hereditary forms often require a high degree of suspicion for diagnosis, as well as specific and specialized management. In addition, a diagnosis of hereditary CRC has major consequences not only for the patient, for whom there are highly effective prevention measures, but also for relatives, who may be carriers of the same condition. The most significant advances in the field of hereditary CRC have occurred in the characterization of serrated polyposis syndrome and in the diagnosis and management of patients with Lynch syndrome and familial adenomatous polyposis.

Serrated polyposis syndrome and the role of serrated polyps in colorectal cancer development

SUMMARY Serrated polyposis syndrome is characterized by the presence of multiple colorectal serrated polyps and is associated with an increased colorectal cancer risk. The mixture of distinct precursor lesion types and malignancies in serrated polyposis syndrome provides a unique model to study the recently proposed serrated neoplasia pathway. This pathway involves the progression of serrated polyps, that is, hyperplastic polyps, sessile serrated adenoma/polyps and/or traditional serrated adenomas, to colorectal cancer. The early genetic events of this route, as currently identified, are BRAF or KRAS mutations and an enhanced CPG island methylation status of multiple genes. There is evidence to suggest that a proportion of sporadic colorectal cancers originate from serrated polyps, which encompass molecular sequences of events such as hypermethylation of different genes and BRAF mutations. This review discusses the characteristics and clinical relevance of serrated polyps and provides an overview of the clinical aspects and treatment of serrated polyposis syndrome.

Linkage to chromosome 2q32.2-q33.3 in familial serrated neoplasia (Jass syndrome)

Causative genetic variants have to date been identified for only a small proportion of familial colorectal cancer (CRC). While conditions such as Familial Adenomatous Polyposis and Lynch syndrome have well defined genetic causes, the search for variants underlying the remainder of familial CRC is plagued by genetic heterogeneity. The recent identification of families with a heritable predisposition to malignancies arising through the serrated pathway (familial serrated neoplasia or Jass syndrome) provides an opportunity to study a subset of familial CRC in which heterogeneity may be greatly reduced. A genome-wide linkage screen was performed on a large family displaying a dominantly-inherited predisposition to serrated neoplasia genotyped using the Affymetrix GeneChip Human Mapping 10 K SNP Array. Parametric and nonparametric analyses were performed and resulting regions of interest, as well as previously reported CRC susceptibility loci at 3q22, 7q31 and 9q22, were followed up by finemapping in 10 serrated neoplasia families. Genome-wide linkage analysis revealed regions of interest at 2p25.2-p25.1, 2q24.3-q37.1 and 8p21.2-q12.1. Finemapping linkage and haplotype analyses identified 2q32.2-q33.3 as the region most likely to harbour linkage, with heterogeneity logarithm of the odds (HLOD) 2.09 and nonparametric linkage (NPL) score 2.36 (P = 0.004). Five primary candidate genes (CFLAR, CASP10, CASP8, FZD7 and BMPR2) were sequenced and no segregating variants identified. There was no evidence of linkage to previously reported loci on chromosomes 3, 7 and 9.

A serrated colorectal cancer pathway predominates over the classic WNT pathway in patients with hyperplastic polyposis syndrome

Hyperplastic polyposis syndrome (HPS) is characterized by the presence of multiple colorectal serrated polyps and is associated with an increased colorectal cancer (CRC) risk. The mixture of distinct precursor lesion types and malignancies in HPS provides a unique model to study the canonical pathway and a proposed serrated CRC pathway in humans. To establish which CRC pathways play a role in HPS and to obtain new support for the serrated CRC pathway, we assessed the molecular characteristics of polyps (n = 84) and CRCs (n = 19) in 17 patients with HPS versus control groups of various sporadic polyps (n = 59) and sporadic microsatellite-stable CRCs (n = 16). In HPS and sporadic polyps, APC mutations were exclusively identified in adenomas, whereas BRAF mutations were confined to serrated polyps. Six of 19 HPS CRCs (32%) were identified in a serrated polyp. Mutation analysis performed in the CRC and the serrated component of these lesions showed identical BRAF mutations. One HPS CRC was located in an adenoma, both components harboring an identical APC mutation. Overall, 10 of 19 HPS CRCs (53%) carried a BRAF mutation versus none in control group CRCs (P = 0.001). Six BRAF-mutated HPS CRCs (60%) were microsatellite unstable owing to MLH1 methylation. These findings provide novel supporting evidence for the existence of a predominant serrated CRC pathway in HPS, generating microsatellite-stable and microsatellite-instable CRCs.

Serrated polyps: critical precursors to colorectal cancer

Colorectal polyps have been traditionally classified as either hyperplastic or adenomatous, with only the latter progressing to carcinoma. However, it is now recognized that certain subtypes of serrated polyps have a risk of malignant transformation via a serrated neoplasia pathway. Serrated polyps are a heterogeneous group of lesions with distinct morphologic, histologic and molecular genetics profiles. Based on available evidence, there are reasons to suspect that this pathway may contribute to interval or missed cancers because serrated lesions are more likely than conventional adenomas to be missed on colonoscopy, and the progression of serrated polyps to cancer may be more rapid. Therefore, it is paramount that physicians recognize the importance of serrated polyps and are aware of the latest surveillance guidelines.

The genomics of colorectal cancer: state of the art

The concept of the adenoma-carcinoma sequence, as first espoused by Morson et al. whereby the development of colorectal cancer is dependent on a stepwise progression from adenomatous polyp to carcinoma is well documented. Initial studies of the genetics of inherited colorectal cancer susceptibility concentrated on the inherited colorectal cancer syndromes, such as Familial Adenomatous Polyposis (FAP) and Lynch Syndrome (also known as HNPCC). These syndromes, whilst easily characterisable, have a well understood sequence of genetic mutations that predispose the sufferer to developing colorectal cancer, initiated for example in FAP by the loss of the second, normal allelle of the tumour supressor APC gene. Later research has identified other inherited variants such as MUTYH (MYH) polyposis and Hyperplastic Polyposis Syndrome. Recent research has concentrated on the pathways by which colorectal adenomatous polyps not due to one of these known inherited susceptibilities undergo malignant transformation, and determination of the types of polyps most likely to do so. Also, why do individuals in certain families have a predisposition to colorectal cancer. In this article, we will discuss briefly the current state of knowledge of the genomics of the classical inherited colorectal cancer syndromes. We will also discuss in detail the genetic changes in polyps that undergo malignant transformation as well as current knowledge with regards to the epigenomic changes found in colorectal polyps.

Up and downregulation of p16(Ink4a) expression in BRAF-mutated polyps/adenomas indicates a senescence barrier in the serrated route to colon cancer

P16(Ink4a) is an important factor in carcinogenesis and its expression can be linked to oncogene-induced senescence. Oncogene-induced senescence is characterized by growth arrest and occurs as a consequence of oncogene activation due to KRAS or BRAF mutation. It has been shown that the induction of p16(Ink4a) in premalignant lesions and its loss during malignant transformation is an important mechanism in the carcinogenesis of several tumours. Loss of p16(Ink4a) is often caused by CDKN2A promoter hypermethylation. This mechanism of gene silencing is associated with the CpG island methylator phenotype (CIMP) in colorectal carcinomas, which is characterized by widespread promoter methylation. In particular, colorectal carcinomas with BRAF mutations have been shown to be strongly associated with CIMP. Also, BRAF mutations are strongly correlated with the serrated route to colorectal cancer. In this study, we investigated p16(Ink4a) expression and promoter methylation in BRAF-mutated serrated lesions of the colon. P16(Ink4a) expression was found to be upregulated in premalignant lesions and was lost in invasive serrated carcinomas. P16(Ink4a) expression and Ki67 expression were mutually exclusive, indicating that p16(Ink4a) acts as cell cycle inhibitor. Additionally, progression of malignant transformation in serrated lesions was accompanied by increasing methylation of the CDKN2A promoter. Therefore, our data provide evidence for oncogene-induced senescence in the serrated route to colorectal cancer with BRAF mutation and upregulation of p16(Ink4a) expression appears to be a useful indicator of induction of senescence. Loss of p16(Ink4a) expression occurs during malignant transformation and is caused mainly by aberrant methylation of the CDKN2A promoter.

Serrated polyposis: an enigmatic model of colorectal cancer predisposition

Serrated polyposis has only recently been accepted as a condition which carries an increased personal and familial risk of colorectal cancer. Described over four decades ago, it remains one of the most underrecognized and poorly understood of all the intestinal polyposes. With a variety of phenotypic presentations, it is likely that serrated polyposis represents a group of diseases rather than a single entity. Further, neoplastic progression in serrated polyposis may be associated with premature aging in the normal mucosa, typified by widespread gene promoter hypermethylation. From this epigenetically altered field, arise diverse polyps and cancers which show a range of molecular features. Despite a high serrated polyp count, only one-third of colorectal cancers demonstrate a BRAF V600E mutation, the molecular hallmark of the canonical serrated pathway, suggesting that though multiple serrated polyps act as a marker of an abnormal mucosa, the majority of CRC in these patients arise within lesions other than BRAF-mutated serrated polyps.

Defining phenotypes and cancer risk in hyperplastic polyposis syndrome

BACKGROUND

Hyperplastic polyposis syndrome is a rare syndrome of colorectal cancer predisposition. Patterns of inheritance of hyperplastic polyposis syndrome are not obvious and the clinical definition is relatively arbitrary. We hypothesize that there are multiple phenotypes included in what is currently called hyperplastic polyposis syndrome. We performed this review of a large series of patients who presented with multiple serrated polyps to look for clinical patterns that may confirm our hypothesis.

METHODS

Hereditary colorectal cancer, colonoscopy, and clinical databases from a single institution were queried for patients meeting the following criteria: 1) ≥ 20 serrated colorectal polyps; 2) ≥ 5 serrated polyps proximal to the sigmoid; 3) ≥ 2 serrated polyps ≥ 10 mm in size; 4) any serrated polyps in a person with at least one first-degree relative who has hyperplastic polyposis syndrome. Records were reviewed for demographics, polyp details, and personal or family history of colorectal extracolonic malignancy.

RESULTS

One-hundred fifteen patients were included. Median age at diagnosis was 62 years and 56% were male. Ninety-seven percent were white. Twenty-five percent of patients had a personal history and 38% had a family history of colorectal cancer. Twenty-eight percent of patients had a personal history and 54% had a family history of extracolonic cancer. Phenotype analysis identified 3 patterns: relatively few large, right-sided polyps (n = 55), many small left-sided polyps (n = 18), and a combination of both left- and right-sided polyps (n = 42). The right-sided phenotype had more sessile serrated polyps and tended to develop colorectal cancer at a younger age.

CONCLUSIONS

There are at least 3 different but overlapping clinical phenotypes within hyperplastic polyposis. Recognizing this clinical heterogeneity is important in defining underlying genetic causes.

The presence of large serrated polyps increases risk for colorectal cancer

BACKGROUND & AIMS

There is evidence that serrated polyps (serrated adenomas and hyperplastic polyps) have different malignant potential than traditional adenomas. We used a colonoscopy database to determine the association between the presence of serrated colorectal polyps and colorectal neoplasia.

METHODS

We performed a multicenter observational study of 10,199 subjects who underwent first-time colonoscopies. Data collected on study subjects included age and sex and the location, size, and histology of polyps or tumors found at colonoscopy. Serrated polyps were defined as those diagnosed by the pathologists in the participating hospitals as a serrated lesion (a lesion given the term of "classical hyperplastic polyp," "traditional serrated adenoma," "sessile serrated adenoma," or "mixed serrated polyp"). Large serrated polyps (LSPs) were defined as those ≥ 10 mm.

RESULTS

There were 1573 patients (15.4%) with advanced neoplasia, 708 patients (6.9%) with colorectal cancer (CRC), and 140 patients (1.4%) with LSPs in our cohort. Multivariate analysis associated the presence of LSPs with advanced neoplasia (odds ratio [OR], 4.01; 95% confidence interval [CI], 2.83-5.69) and CRC (OR, 3.34; 95% CI, 2.16-5.03). The presence of LSPs was the greatest risk factor for CRC, particularly for proximal CRC (OR, 4.79; 95% CI, 2.54-8.42). Proximal and protruded LSPs were the highest risk factors for proximal CRC (OR, 5.36; 95% CI, 2.40-10.8 and OR, 9.00; 95% CI, 2.75-19.2, respectively).

CONCLUSIONS

The presence of LSPs is a risk factor for CRC, particularly CRC of the proximal colon.

Risk factors: Hyperplastic polyposis syndrome and risk of colorectal cancer

Hyperplastic polyposis syndrome is a widely accepted, but poorly understood, risk factor for colorectal cancer. A recent report has laid the foundations for improving the management of patients with this enigmatic disorder by identifying the features associated with colorectal cancer risk, as well as estimating the magnitude of this risk.

Proximal and large hyperplastic and nondysplastic serrated polyps detected by colonoscopy are associated with neoplasia

BACKGROUND & AIMS

The family of serrated lesions includes hyperplastic polyps and sessile serrated adenomas without dysplasia, as well as traditional serrated adenoma with dysplasia. We investigated whether detection of proximal nondysplastic serrated polyps (ND-SP) at screening and surveillance colonoscopies is associated with advanced neoplasia.

METHODS

The study included 3121 asymptomatic patients (aged 50-75 years) who had screening colonoscopies; 1371 had subsequent surveillance. The proximal colon was defined as segments proximal to the descending colon. Large ND-SP were defined as ≥ 10 mm. We compared rates of detection of any neoplasia and advanced neoplasia at screening and surveillance colonoscopies (within 5.5 years) in patients with and without proximal or large ND-SP.

RESULTS

At baseline screening, 248 patients (7.9%) had at least 1 proximal ND-SP. They were more likely than patients with no proximal ND-SP to have advanced neoplasia (17.3% vs 10.0%; odds ratio [OR], 1.90; 95% confidence interval [CI], 1.33-2.70). Patients with large ND-SP (n = 44) were also more likely to have synchronous advanced neoplasia (OR, 3.37; 95% CI, 1.71-6.65). During surveillance, 39 patients with baseline proximal ND-SP and no neoplasia were more likely to have neoplasia compared with subjects who did not have polyps (OR, 3.14; 95% CI, 1.59-6.20). Among patients with advanced neoplasia at baseline, those with proximal ND-SP (n = 43) were more likely to have advanced neoplasia during surveillance (OR, 2.17; 95% CI, 1.03-4.59).

CONCLUSIONS

Detection of proximal and large ND-SP at a screening colonoscopy is associated with an increased risk for synchronous advanced neoplasia. Detection of proximal ND-SP in a baseline colonoscopy is associated with an increased risk for interval neoplasia during surveillance.

Lessons from Lynch syndrome: a tumor biology-based approach to familial colorectal cancer

Colorectal cancer (CRC) develops within precursor lesions in the single-celled epithelial lining of the gut. The two most common epithelial lesions are the adenoma and the serrated polyp. CRC is also one of the most familial of the common cancers, and just as there are syndromes associated with increased risk of CRC arising in adenomas, there are also syndromes with increased CRC risk associated with serrated polyps. In this article, we describe the features of such a syndrome, familial serrated neoplasia, which distinguish it from the well-characterized condition Lynch syndrome (or hereditary nonpolyposis CRC), and show that the molecular pathology of tumors forms the basis for this distinction. Lynch syndrome CRC arises almost exclusively within adenomatous precursor lesions, in contrast with familial serrated neoplasia where at least half of the cancers develop in serrated polyps. Finally, rare families exist in which both conditions segregate independently, producing a difficult diagnostic picture.