Association between lifestyle and dietary preference factors and conventional adenomas and serrated polyps

Introduction

Both conventional adenoma (AD) and serrated polyp (SP) were known precursor lesions of colorectal cancer (CRC). Modifiable lifestyle factors were significantly associated with CRC risk, but whether these factors were related to the risk of different precursors of CRC needed to be clarified. This study aimed to evaluate the risks of AD and SP caused by lifestyle factors and compare the risk differences between AD and SP.

Methods

The study population was from the CRC screening cohort in Hangzhou, China. A total of 458,457 eligible individuals volunteered to undergo initial screening including the fecal immunochemical test (FIT) and the CRC risk assessment. Finally, 13,993 participants who had undergone colonoscopy tests and had been diagnosed at designated hospitals were selected in this study. All participants were required to fill out a questionnaire during the initial screening for collecting their information. The generalized estimate equation (GEE) model was used to assess the association between lifestyle factors/dietary preferences and AD/SP.

Results

The body mass index (BMI) and smoking were positively associated with the risks of only SP (BMI: OR = 1.50, 95%CI: 1.23-1.84; smoking: OR = 1.29, 95%CI: 1.07-1.55), only AD (BMI: OR = 1.53, 95%CI: 1.28-1.82; OR = 1.24, 95%CI: 1.11-1.39), and synchronous SP and AD (BMI: OR = 1.97, 95%CI: 1.40-2.75; smoking: OR = 1.53, 95%CI: 1.27-1.85). In the case-group comparison, smoking was more strongly associated with the risk of synchronous SP and AD than only AD. Alcohol drinking was positively associated with the risk of AD (OR = 1.28, 95%CI: 1.14-1.44), but no statistically significant difference was observed in risks in the case-group comparison. Furthermore, whole-grain intake was associated with a decreased risk of only AD (OR = 0.78, 95%CI: 0.65-0.93). However, white meat intake was positively associated with risks of only SP when compared with AD cases (OR = 1.60, 95%CI: 1.15-2.23).

Conclusion

The current study identified common risk factors such as BMI and smoking as well as different risks of certain factors (e.g., alcohol drinking and whole-grain intake) for SP and AD. However, there were still some factors, especially diet-related factors, that have not been fully elucidated in their association with the two lesions. Further research is needed in future to confirm and develop prevention strategies for different lesions.

Commensal Fecal Microbiota Profiles Associated with Initial Stages of Intestinal Mucosa Damage: A Pilot Study

Progressive intestinal mucosal damage occurs over years prior to colorectal cancer (CRC) development. The endoscopic screening of polyps and histopathological examination are used clinically to determine the risk and progression of mucosal lesions. We analyzed fecal microbiota compositions using 16S rRNA gene-based metataxonomic analyses and the levels of short-chain fatty acids (SCFAs) using gas chromatography in volunteers undergoing colonoscopy and histopathological analyses to determine the microbiota shifts occurring at the early stages of intestinal mucosa alterations. The results were compared between diagnosis groups (nonpathological controls and polyps), between samples from individuals with hyperplastic polyps or conventional adenomas, and between grades of dysplasia in conventional adenomas. Some microbial taxa from the Bacillota and Euryarchaeota phyla were the most affected when comparing the diagnosis and histopathological groups. Deeper microbiota alterations were found in the conventional adenomas than in the hyperplastic polyps. The Ruminococcus torques group was enriched in both the hyperplastic polyps and conventional adenomas, whereas the family Eggerthellaceae was enriched only in the hyperplastic polyps. The abundance of Prevotellaceae, Oscillospiraceae, Methanobacteriaceae, Streptococcaceae, Christensenellaceae, Erysipelotrichaceae, and Clostridiaceae shifted in conventional adenomas depending on the grade of dysplasia, without affecting the major SCFAs. Our results suggest a reorganization of microbial consortia involved in gut fermentative processes.

Are Non-dysplastic Crypts with Corrupted Shapes the Initial Recordable Histological Event in the Development of Sporadic Conventional Adenomas?

BACKGROUND

Colonic crypts with normal epithelial lining displaying corrupted shapes (called non-dysplastic crypts with corrupted shapes, NDCs) were earlier recorded underneath the adenomatous glands of conventional colon adenomas in rats.

AIM

To assess the frequency of NDCs in clinical sporadic conventional (tubular/villous) adenomas.

MATERIALS AND METHODS

NDCs found underneath the adenomatous epithelium in 255 sporadic conventional adenomas removed at endoscopy were classified into four groups: i) With fission distortions, ii) with length distortions, iii) with outline distortions, and iv) with axial polarity distortions. In 22 controls, the colonic mucosa proximal or distal to surgically removed colonic adenocarcinomas was scrutinized for NDCs.

RESULTS

Nearly three-quarters of the sporadic conventional adenomas investigated here had three or more NDCs underneath the adenomatous tissue, those with ≥4 NDCs being more frequent (46.3%) than those having 1, 2 or 3 NDCs (p<0.05). Nineteen out of the 22 control colon segments had normal crypts and the remaining three had occasional NDCs (mean=3.7, range=2-5).

CONCLUSION

NDCs were found underneath the adenomatous glands in all 255 sporadic conventional adenomas. Occasionally, NDCs were present in the mucosa of the stalk of pediculated conventional adenomas. The absence of adenomatous tissue in NDCs of the stalk should rule out the possibility that the adenomatous tissue on top had directly orchestrated the development of NDCs below. Moreover, NDCs rarely occurred in controls. Accordingly, NDCs emerge as a genuine phenomenon of crypt deformation in sporadic conventional adenomas. Considering that human colonic crypts typically divide at most once or twice during a lifetime, with an average crypt cycle length of 36 years, the accumulation of NDCs underneath sporadic conventional adenomas is remarkable. In light of these considerations, it is suggested that these putative mutated NDCs may represent the initial histological recordable event heralding the development of sporadic conventional adenomas in the human colon.

Maspin, a Marker of Serrated Colorectal Polyps

The serine proteinase inhibitor maspin is a tumor-suppressor protein that stimulates apoptosis and inhibits motility, invasion and cancer metastasis. Mutant maspin galvanises partial loss of tumor-suppressor function, reducing susceptibility to apoptosis and facilitating malignant progression. Mutant maspin has been reported in many tumor types. We recently analyzed maspin expression in 128 colorectal lesions: 39 hyperplastic polyps (HPs), 29 sessile serrated adenoma/polyps (SSA/Ps), three traditional serrated adenomas (TSAs), 20 conventional colorectal adenomas (CCRAs), 5 carcinomas evolving from CCRA, 12 active inflammatory bowel disease (IBD), 2 ulcerative colitis (UC) in remission, 4 solitary ulcers (rectum) and 12 normal colorectal mucosa. The topographic distribution of maspin in the cytoplasm was classified into i) extensive, ii) focal, or iii) negative. The intensity of maspin expression in the cytoplasm was classified into i) unquestionable or ii) negative. Cases with faint (questionable) maspin expression were also recorded as negative. Extensive maspin expression was recorded in 95% (39/41) of the HPs, in 100% (29/29) of the SSA/Ps (including one carcinoma arising in a SSA/P), in 66% (2/3) of the TSAs, but only in 10% (2/20) of the CCRAs. None of the specimens with carcinoma arising in CCRA, with UC in remission or with solitary ulcer exhibited extensive maspin expression. Importantly, maspin was not expressed in the normal mucosa (including that adjacent to HP, SSA/P, TSA and CCRA). It is submitted that extensive maspin expression might be a manifestation of mutant maspin in lesions central to the serrated pathway of colorectal carcinogenesis.

Maspin highlights colorectal serrated polyps: preliminary findings

AIMS

Maspin, a 42-kDa serine proteinase inhibitor, is a tumor suppressor protein that stimulates apoptosis and inhibits motility, invasion and cancer metastasis. Mutant maspin leads to partial loss of tumor suppressor function, decreased susceptibility to apoptosis and to malignant progression. We recently found maspin expression (ME) in the cytoplasm of serrated colonic lesions, such as hyperplastic polyps (HP) and sessile serrated adenoma/polyps (SSA/P).

MATERIALS AND METHODS

ME was investigated in 10 colorectal lesions: three HP, three SSA/P and four conventional colorectal adenomas (CCRA).

RESULTS

Widespread cytoplasmic ME (comprising the entire height and width of the lesion) was present in the three HP and in the three SSA/P. In contrast, ME was only focally expressed in the four CCRA. ME was not present in the normal mucosa adjacent to those lesions.

CONCLUSION

These preliminary findings suggest that maspin might be of help in discriminating between serrated colonic lesions (HP and SSA/P) and CCRA.

β-catenin helices in the cytoplasm of sessile serrated adenoma/polyps and conventional colorectal adenomas

Initiation and progression in conventional adenomas is triggered by deregulation of WNT/β-catenin signaling. In the absence of WNT signal (off-state), β-catenin prevents phosphorylation of GSK3β, leading to aberrant nuclear accumulation in human tumors. It has been postulated that mutations in the β-catenin gene are always associated with a morphologically-neoplastic course. While investigating the nuclear expression of β-catenin in 170 colorectal biopsies, we observed a non-previously reported phenomenon, namely the presence of β-catenin cytoplasmic helices in 29% (n=7) of 24 sessile serrated adenoma/polyps (SSA/P), in 24% (n=13) of 54 adenomas, in 8% (n=3) of 38 specimens with IBD, but in none (0/54) with normal mucosa. The earliest β-catenin helices were found at the bottom of SSA/P glands (the domain of stem cells in the colorectal mucosa). It is submitted that β-catenin helices might highlight a non-previously described cytoplasmic phenomenon evolving during the serrated-carcinoma pathway in SSA/P, and during the adenoma-carcinoma pathway in conventional adenomas.