Prevalence and risk factors of colorectal cancer in Asia

Soy Metabolism by Gut Microbiota from Patients with Precancerous Intestinal Lesions

BACKGROUND

Colorectal cancer (CRC) requires the presence of a variety of factors predisposing a tumorigenic milieu. Excluding familial clustering and hereditary CRC syndromes, the development of sporadic CRC from precancerous lesions is influenced by tissue inflammation, modulation of intestinal immunity, hormones, dietary habits and gut microbiota composition. As concerning the last two aspects, the intestinal presence of equol, the most biologically active metabolite of the soy isoflavone daidzein and the presence of a genetic determinant of gut microbiota able to metabolize daidzein, seem to lower the CRC risk. It has been hypothesized that the anaerobic microorganisms of the Bacteroides genus play a role in equol production.

AIM

To evaluate the presence of (i) anaerobic gut microbiota and (ii) the urinary levels of soy isoflavones (daidzein, genistein and equol) in patients with and without precancerous lesions, challenged with a daidzein-rich soy extract.

METHODS

Consecutive subjects undergoing colonoscopy participated to the study. Feces were collected from all patients one week before colonoscopy for gut microbiota studies. After the endoscopy examination and the histological evaluation, 40 subjects, 20 with sporadic colorectal adenomas (SCA/P group) and 20 without proliferative lesions (control group) were enrolled for the study. Urine levels of soy isoflavones daidzein, genistein and their metabolite equol, were determined by high performance liquid chromatographic (HPLC) analysis and gut microbiota analysis was performed by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) procedure.

RESULTS

Seventeen different bacterial species were identified in the fecal samples of the forty subjects participating to the study. Ten bacterial species resulted anaerobic Gram-negative bacteria, all belonging to the Bacteroides genus. A significant difference of bacteria species was evidenced in the fecal samples of the two groups of subjects. Particularly important was the evidence of Parabacteroides distasonis, Clostridium clostridioforme and Pediococcus pentasaceus only in control fecal samples, such as the presence of Bacteroides fragilis and Prevotella melaningenica only in SCA/P fecal samples. Concerning the soy isoflavones levels, no statistically significant differences were revealed in the genistein and daidzein urinary levels between the two groups of subjects. On the contrary, urinary equol levels were undetectable in ten SCA/P subjects and in two controls; moreover, when present, the levels of urinary equol were significantly lower in SCA/P subjects compared to controls (0.24 ± 0.27 mg/24 hrs vs. 21.25 ± 4.3 mg/24 hrs, respectively, p = 1.12 × 10^-6).

CONCLUSIONS

Our results suggest that the presence of anaerobic Bacteroides in the colon, and the production of equol from soy, could determine a milieu able to contrast the development of colonic mucosa proliferative lesions.

Current challenges in the implementation of precision oncology for the management of metastatic colorectal cancer

Over the last few decades, molecularly targeted agents have been used for the treatment of metastatic colorectal cancer. They have made remarkable contributions to prolonging the lives of patients. The emergence of several biomarkers and their introduction to the clinic have also aided in guiding such treatment. Recently, next-generation sequencing (NGS) has enabled clinicians to identify these biomarkers more easily and reliably. However, there is considerable uncertainty in interpreting and implementing the vast amount of information from NGS. The clinical relevance of biomarkers other than NGS are also subjects of debate. This review covers controversial issues and recent findings on such therapeutics and their molecular targets, including VEGF, EGFR, BRAF, HER2, RAS, actionable fusions, Wnt pathway and microsatellite instability for comprehensive understanding of obstacles on the road to precision oncology in metastatic colorectal cancer.

Risk of developing metachronous advanced colorectal neoplasia after resection of low-risk diminutive versus small adenomas

BACKGROUND AND AIMS

Current postpolypectomy guidelines classify 1 to 2 diminutive (1-5 mm) nonadvanced adenomas (NAAs) and 1 to 2 small (6-9 mm) NAAs as low-risk adenomas and recommend the same surveillance interval for both lesions. We compared the risk of metachronous advanced colorectal neoplasia (ACRN) for both groups.

METHODS

We studied 8602 patients who underwent removal of ≥1 NAA and follow-up colonoscopic surveillance. Patients were categorized into 4 groups based on size and number of baseline NAAs: group 1, ≤2 diminutive NAAs (n = 6379); group 2, ≤2 small NAAs (n = 1672); group 3, ≥3 diminutive NAAs (n = 293); and group 4, ≥3 small NAAs (n = 258). Size was classified based on the largest NAA.

RESULTS

The 5-year cumulative incidence rates of metachronous ACRN in groups 1, 2, 3, and 4 were 2.7%, 5.1%, 10.7%, and 15.1%, respectively. Groups 2, 3, and 4 had a higher risk of metachronous ACRN than group 1. Compared with group 1, the adjusted hazard ratios for metachronous ACRN were 2.06 (95% confidence interval [CI], 1.46-2.91) for group 2, 2.75 (95% CI, 1.53-4.96) for group 3, and 4.49 (95% CI, 2.62-7.70) for group 4. However, the risk of metachronous ACRN was not significantly different between groups 3 and 4 (adjusted hazard ratio, 1.62; 95% CI, .76-3.44).

CONCLUSIONS

Among patients with ≤2 NAAs, patients with 1- to 5-mm NAAs had a lower risk of metachronous ACRN than those with 6- to 9-mm NAAs. The guidelines should consider extending surveillance intervals in patients with ≤2 diminutive NAAs.

The relationship between metabolic syndrome and the incidence of colorectal cancer

OBJECTIVES

This study evaluated the incidence of colorectal cancer (CRC) according to the number of metabolic syndrome (MetS) components.

METHODS

Using health checkup and insurance claims data of 6,365,409 subjects, the occurrence of CRC according to stage of MetS by sex was determined from the date of the health checkup in 2009 until December 31, 2018.

RESULTS

Cumulative incidence rates (CIR) of CRC in men and women was 3.9 and 2.8 per 1000 (p < 0.001), respectively. CIR of CRC for the normal, pre-MetS, and MetS groups in men was 2.6, 3.9, and 5.5 per 1000 (p < 0.001) and CIR in women was 2.1, 2.9, and 4.5 per 1000 (p < 0.001), respectively. Compared with the normal group, the hazard ratio (HR) of CRC for the pre-MetS group was 1.25 (95% CI 1.17-1.33) in men and 1.09 (95% CI 1.02-1.17) in women, and the HR of CRC for the MetS group was 1.54 (95% CI 1.43-1.65) in men and 1.39 (95% CI 1.26-1.53) in women after adjustment.

CONCLUSIONS

We found that MetS is a risk factor for CRC in this study. Therefore, the prevention and active management of MetS would contribute to the prevention of CRC.

Clinical outcomes of submucosal colorectal cancer diagnosed after endoscopic resection: a focus on the need for surgery

Background/Aims

We aimed to investigate the proportion of and risk factors for residual cancer and/or lymph node metastasis after surgery was performed because of high-risk pathological features in endoscopic resection specimen of suspected superficial submucosal colorectal cancer (SSMC).

Methods

We reviewed medical records of 497 patients (58.8 ± 9.8 years, 331 males) undergoing endoscopic resection of suspected SSMC. High-risk pathological features included: deep submucosal cancer invasion ≥ 1,000 μm; positive lymphovascular and/or perineural invasion; poorly differentiated adenocarcinoma; and positive resection margin. We investigated the occurrence of additional surgery and residual cancer and/or lymph node involvement in the surgical specimen.

Results

En bloc resection was performed in 447 patients (89.9%). High-risk pathological features were detected in 372 patients (74.8%). Additional surgery was performed in 336 of 372 patients with high-risk pathological features. Of these, 47 surgical specimens (14.0%) showed residual cancer and/or lymph node metastasis. Piecemeal resection was more common in those with residual cancer and/or lymph node involvement than those without (9/47 [19.1%] vs. 24/289 [8.3%], P= 0.032). Positive resection margin was also significantly associated with positive residual cancer and/or lymph node involvement. As the number of high-risk pathological features increased, the risk of regional lymph node metastasis increased proportionally (P= 0.002).

Conclusions

High-risk pathological features were frequently detected after endoscopic resection of suspected SSMC while residual cancer and/or lymph node metastasis were not commonly present in the additional surgical specimen. Further optimized strategy for proper endoscopic management of suspected SSMC is necessary.

Cytotoxin-associated gene A increases carcinogenicity of helicobacter pylori in colorectal adenoma

OBJECTIVE

This study aimed to investigate the correlation of Helicobacter pylori (Hp) infection with disease risk and severity of colorectal adenoma, also to explore the association of cytotoxin-associated gene A (CagA) positive (CagA⁺)-Hp infection with gastrin and ki-67 expressions in colorectal adenoma patients.

METHODS

There were 1000 colorectal adenoma patients and 1500 controls consecutively enrolled, then Hp infection status was determined by ¹⁴C urea breath test and rapid urease test. Also, serum CagA expression and gastrin expression of colorectal adenoma patients were determined by enzyme-linked immunosorbent assay. Ki-67 expression in adenoma tissue of colorectal adenoma patients was assessed using immunohistochemistry.

RESULTS

Hp⁺ rate in colorectal adenoma patients (623 (62.3%)) was more elevated than that in controls (814 (54.3%)). Multivariate logistic regression model analysis disclosed that Hp⁺ was an independent risk factor for colorectal adenoma. Additionally, Hp⁺ was positively associated with tumor size and high-grade intraepithelial neoplasia in colorectal adenoma patients. Also, serum gastrin expression and intratumoral ki-67 expression were higher in Hp⁺ CagA⁺ patients and Hp⁺ CagA^- patients compared to Hp^- patients, and they were also higher in Hp⁺ CagA⁺ patients compared to Hp⁺ CagA^- patients.

CONCLUSION

Hp infection positively associates with higher disease risk and worse disease conditions of colorectal adenoma, and CagA enhances the carcinogenicity of Hp in colorectal adenoma.

Serum vitamin D receptor (VDR) levels as a potential diagnostic marker for colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of mortality and morbidity worldwide, and there has been a significant increase in the incidence of CRC in recent decades. Therefore, there is an urgent need to identify blood biomarkers that can be used for early diagnosis. It is not yet clear whether the level of vitamin D and its receptor, vitamin D receptor (VDR), in the blood are helpful factors in the diagnosis of CRC. Therefore, the study focuses on determining the VDR serum level’s contribution and other chemical parameters to the risk of CRC. A total of 189 Saudi participants (66 CRC patients and 123 control patients) aged 20–80 years old were enrolled in this case-control study. A serum sample was collected from each participant, and the levels of VDR and other bone profile tests were determined using ELISA or chemiluminescent assays. P values < 0.05 were considered statistically significant. The results showed a highly significant reduction in the levels of total vitamin D (P < 0.0001), VDR (P < 0.0001), vitamin D₃ (P < 0.05), and calcium (P < 0.0001) in the serum of CRC patients compared to the controls. However, the alkaline phosphatase level was higher in CRC patients compared to the controls (P < 0.0001). None of the blood markers showed a significant correlation to the progression of CRC (P > 0.05). More investigation is needed to elucidate different physiological processes that can be affected by these blood biomarkers, therefore changing the carcinogenesis of CRC.

miR-7112-3p targets PERK to regulate the endoplasmic reticulum stress pathway and apoptosis induced by photodynamic therapy in colorectal cancer CX-1 cells

BACKGROUND

Colorectal cancer (CRC) is the third most common malignant tumor worldwide. Photodynamic therapy (PDT) is an emerging modality for the treatment of solid tumors. Sinoporphyrin sodium (DVDMS) is a new photosensitizer with good therapeutic killing effects on cancer cells. Recent findings have shown that microRNAs play important roles in many biological processes. However, the functions of microRNAs in DVDMS-induced PDT remain largely unclear.

MATERIALS AND METHODS

Proteins involved in endoplasmic reticulum (ER) stress and apoptosis of CX-1 cells treated with DVDMS-PDT were examined by Western blotting and cell viability assays. 15 candidate miRNAs targeting RNA-dependent protein kinase-like ER kinase (PERK) were screened and verified using the TargetScan, miRWalk and miRDB databases. The downstream pathways of candidate miRNAs with high scores were studied by cell transfection, qRT-PCR, Western blotting and dual-luciferase reporter assays. The subcellular location of DVDMS was confirmed by laser confocal microscopy.

RESULTS

DVDMS-PDT induced apoptosis via elevated ER stress and activation of the PERK/ATF4/CHOP/caspase cascade pathway in CX-1 cells. The endoplasmic reticulum was involved in the subcellular accumulation of DVDMS in CX-1 cells. Dual-luciferase reporting experiment confirmed that a direct crosslinking between miR-7112-3p and PERK. In addition, miR-7112-3p was highly expressed in CRC tissues compared with peripheral tissues.

CONCLUSION

Our work showed that miR-7112-3p directly targeted PERK and further regulated PERK/ATF4/CHOP/caspase cascade pathway, resulting in enhanced apoptosis in CX-1 cells treated with DVDMS-PDT.

Assessing knowledge on preventive colorectal cancer screening in Saudi Arabia: A cross-sectional study

Context

According to the Saudi Cancer Registry's 2014 Cancer Incidence Report, colorectal cancer (CRC) is the leading form of malignant cancer among Saudi men and ranks third among women. Raising awareness about CRC risk factors could lead to a significant decline in incidence of disease.

Aims

To assess CRC awareness and evaluate the main barriers that might prevent individuals' participation in screening.

Settings and Design

A self-administered survey was conducted over two days as part of a CRC awareness campaign in Jeddah, Saudi Arabia in March, 2018.

Methods and Materials

The survey addressed issues regarding knowledge of CRC and available screening methods. The survey also examined barriers that might make one reluctant to undergo preventative screening. Stata/SE 15.0 was used for all statistical analyses.

Statistical Analyses

Continuous variables were described with frequencies and percentages. Stepwise linear regression models were constructed to predict CRC knowledge and barriers.

Results

Out of 422 participants, 50.2% were men. Most respondents were between 15-35 years old (65.8%). Multivariate analysis revealed that gender was a significant predictor of CRC knowledge. Furthermore, the variables of education and family history of CRC significantly predicted subjects' awareness of colonoscopic screenings. The most common barriers for seeking screening included fear of the procedure, absence of clinical symptoms, and fear of the results.

Conclusions

Our results highlight deficits in public CRC knowledge and their awareness of preventative measures. These shortcomings were found to be mainly related to education level. Specific barriers affecting screening decisions were also identified; intensive efforts on awareness to overcome these obstacles will be required.