Microarray profiling of colorectal cancer in Bangladeshi patients

Association between Gastric Cancer with Behavioral and Dietary Factors: A Hospital Based Case-Control Study in South Asia

Background Gastric cancer (GC) is one of the most common malignancies and a leading cause of mortality and morbidity worldwide. It is the fourth leading cancer in Bangladesh. Identification of risk factors, effective prevention, and early diagnosis are the most important interventions against GC.

Objectives To find an association of dietary and behavioral factors in the development of GC among the Bangladeshi population.

Methods This case–control study was conducted from January 2017 to December 2018 at the National Institute of Cancer Research and Hospital, Dhaka, Bangladesh. A total of 178 patients were studied (89 case and 89 controls). Data were collected via face-to-face interview using a standard structured questionnaire, posing questions about socio-demographic, behavioral and dietary habits, and clinical factors. A binary logistic regression method was used to calculate the odds ratio (OR).

Results Among 178 patients, the age group ranged from 30 to 80 years and most patients were between 51 to 60 years. The results showed that regular consumption of red meat, duration of smoking, smokeless tobacco, fast food and fatty food, and family history of any type of cancer were directly associated with the risk of GC. On the contrary, a habit of regular walking and playing sports has an inverse association with GC. Adjusted OR shows regular consumption of red meat has 2.6 times more risk (OR = 2.661) of developing GC compared with irregular meat consumption, and a person with a history of Helicobacter pylori infection is 53% (OR = 7.263; 95% confidence interval: 3.614–14.597) more likely to develop cancer. In contrast, people who were doing exercise regularly for at least 30 minutes/day are 62.7% (OR = 0.373) less likely to develop GC than those who did not.

Conclusion The study showed an association of some dietary and behavioral factor in the development of GC. However, more research in this field is required to understand the etiology, for the development of suitable screening test, for demarcation of high-risk population, and to develop and evaluate the effectiveness of primary prevention programs.

Beyond cancer genes: colorectal cancer as robust intrinsic states formed by molecular interactions

Colorectal cancer (CRC) has complex pathological features that defy the linear-additive reasoning prevailing in current biomedicine studies. In pursuing a mechanistic understanding behind such complexity, we constructed a core molecular–cellular interaction network underlying CRC and investigated its nonlinear dynamical properties. The hypothesis and modelling method has been developed previously and tested in various cancer studies. The network dynamics reveal a landscape of several attractive basins corresponding to both normal intestinal phenotype and robust tumour subtypes, identified by their different molecular signatures. Comparison between the modelling results and gene expression profiles from patients collected at the second affiliated hospital of Zhejiang University is presented as validation. The numerical ‘driving’ experiment suggests that CRC pathogenesis may depend on pathways involved in gastrointestinal track development and molecules associated with mesenchymal lineage differentiation, such as Stat5, BMP, retinoic acid signalling pathways, Runx and Hox transcription families. We show that the multi-faceted response to immune stimulation and therapies, as well as different carcinogenesis and metastasis routes, can be straightforwardly understood and analysed under such a framework.

Analysis of colorectal cancers in British Bangladeshi identifies early onset, frequent mucinous histotype and a high prevalence of RBFOX1 deletion

Background

Prevalence of colorectal cancer (CRC) in the British Bangladeshi population (BAN) is low compared to British Caucasians (CAU). Genetic background may influence mutations and disease features.

Methods

We characterized the clinicopathological features of BAN CRCs and interrogated their genomes using mutation profiling and high-density single nucleotide polymorphism (SNP) arrays and compared findings to CAU CRCs.

Results

Age of onset of BAN CRC was significantly lower than for CAU patients (p=3.0 x 10^-5) and this difference was not due to Lynch syndrome or the polyposis syndromes. KRAS mutations in BAN microsatellite stable (MSS) CRCs were comparatively rare (5.4%) compared to CAU MSS CRCs (25%; p=0.04), which correlates with the high percentage of mucinous histotype observed (31%) in the BAN samples. No BRAF mutations was seen in our BAN MSS CRCs (CAU CRCs, 12%; p=0.08). Array data revealed similar patterns of gains (chromosome 7 and 8q), losses (8p, 17p and 18q) and LOH (4q, 17p and 18q) in BAN and CAU CRCs. A small deletion on chromosome 16p13.2 involving the alternative splicing factor RBFOX1 only was found in significantly more BAN (50%) than CAU CRCs (15%) cases (p=0.04). Focal deletions targeting the 5’ end of the gene were also identified. Novel RBFOX1 mutations were found in CRC cell lines and tumours; mRNA and protein expression was reduced in tumours.

Conclusions

KRAS mutations were rare in BAN MSS CRC and a mucinous histotype common. Loss of RBFOX1 may explain the anomalous splicing activity associated with CRC.

A genome-wide study of cytogenetic changes in colorectal cancer using SNP microarrays: opportunities for future personalized treatment

In colorectal cancer (CRC), chromosomal instability (CIN) is typically studied using comparative-genomic hybridization (CGH) arrays. We studied paired (tumor and surrounding healthy) fresh frozen tissue from 86 CRC patients using Illumina's Infinium-based SNP array. This method allowed us to study CIN in CRC, with simultaneous analysis of copy number (CN) and B-allele frequency (BAF)--a representation of allelic composition. These data helped us to detect mono-allelic and bi-allelic amplifications/deletion, copy neutral loss of heterozygosity, and levels of mosaicism for mixed cell populations, some of which can not be assessed with other methods that do not measure BAF. We identified associations between CN abnormalities and different CRC phenotypes (histological diagnosis, location, tumor grade, stage, MSI and presence of lymph node metastasis). We showed commonalities between regions of CN change observed in CRC and the regions reported in previous studies of other solid cancers (e.g. amplifications of 20q, 13q, 8q, 5p and deletions of 18q, 17p and 8p). From Therapeutic Target Database, we identified relevant drugs, targeted to the genes located in these regions with CN changes, approved or in trials for other cancers and common diseases. These drugs may be considered for future therapeutic trials in CRC, based on personalized cytogenetic diagnosis. We also found many regions, harboring genes, which are not currently targeted by any relevant drugs that may be considered for future drug discovery studies. Our study shows the application of high density SNP arrays for cytogenetic study in CRC and its potential utility for personalized treatment.

Colorectal carcinoma in young adults: a retrospective study on Indian patients: 2000-2008

AIM

To highlight an increased incidence of colorectal cancer (CRC) amongst young Indian adults.

METHOD

A retrospective study of 305 cases of CRC admitted to SSKM Hospital, Kolkata, India during 2000-2008 was carried out.

RESULTS

The ratio (0.64) of under-40 to above-40 CRC patients reported in this study is comparable to those from premier Oncology Centers in India (∼0.52) and is higher than those in the Indian National Cancer Registry (∼0.20) and international average (0.07). Distinctive tumour characteristics in younger patients including left-sided lesion (69.7%), presentation at an advanced (III/IV) stage (60%), poor histological differentiation (50%) and predominance of mucin-secreting adenocarcinoma (80%) are similar to those reported in the international literature. Some features are suggestive of hereditary non polyposis colorectal cancer syndrome, which may be a possible reason for the high proportion of young CRC patients.

CONCLUSION

A high index of suspicion for CRC among young Indian adults is necessary.

Rectal cancer in young adults: a series of 102 patients at a tertiary care centre in India

OBJECTIVE

Rectal cancer in young patients is uncommon. There is little information on rectal cancer in young adults in India. The aim of this study was to determine the relative incidence of rectal cancer in young patients in India and identify any differences in histological grade and pathological stage between younger and older cohorts.

METHOD

All adult patients presenting at a tertiary colorectal unit with primary rectal adenocarcinoma between September 2003 and August 2007 were included. Patients were divided into two groups: 40 years and younger, and older than 40 years. Details regarding patient demographics, preoperative assessment, management and tumour grade and stage were obtained from a prospectively maintained database.

RESULTS

One hundred and two of 287 patients (35.5%) were 40 or younger at presentation. Younger patients were more likely to present with less favourable histological features (52.0% vs 20.5% (P < 0.001)) and low rectal tumours (63.0% vs 50.0%) (P = 0.043), but were equally likely to undergo curative surgery compared to the older group (P = 0.629). Younger patients undergoing surgery had a higher pathological T stage (T0-2 18.9%, T3 62.3%, T4 19.7% vs 34.5%, 56.0%, 9.5%) (P = 0.027) and more advanced pathological N stage (N0 31.1%, N1 41.0%, N2 27.9% vs 53.4%, 26.7%, 17.2%) (P = 0.014).

CONCLUSION

The relative number of young patients with rectal cancer in this Indian series is higher than figures reported in western populations. The reasons for this are not clear. The histopathological features of rectal tumours in young patients in this study are consistent with similar studies in Western populations.