Kras Gene Mutation and RASSF1A, FHIT and MGMT Gene Promoter Hypermethylation: Indicators of Tumor Staging and Metastasis in Adenocarcinomatous Sporadic Colorectal Cancer in Indian Population

Abstract

ObjectiveColorectal cancer (CRC) development involves underlying modifications at genetic/epigenetic level. This study evaluated the role of Kras gene mutation and RASSF1A, FHIT and MGMT gene promoter hypermethylation together/independently in sporadic CRC in Indian population and correlation with clinicopathological variables of the disease.MethodsOne hundred and twenty four consecutive surgically resected tissues (62 tumor and equal number of normal adjacent controls) of primary sporadic CRC were included and patient details including demographic characteristics, lifestyle/food or drinking habits, clinical and histopathological profiles were recorded. Polymerase chain reaction - Restriction fragment length polymorphism and direct sequencing for Kras gene mutation and Methylation Specific-PCR for RASSF1A, FHIT and MGMT genes was performed.ResultsKras gene mutation at codon 12 & 13 and methylated RASSF1A, FHIT and MGMT gene was observed in 47%, 19%, 47%, 37% and 47% cases, respectively. Alcohol intake and smoking were significantly associated with presence of Kras mutation (codon 12) and MGMT methylation (p-value <0.049). Tumor stage and metastasis correlated with presence of mutant Kras codon 12 (p-values 0.018, 0.044) and methylated RASSF1A (p-values 0.034, 0.044), FHIT (p-values 0.001, 0.047) and MGMT (p-values 0.018, 0.044) genes. Combinatorial effect of gene mutation/methylation was also observed (p-value <0.025). Overall, tumor stage 3, moderately differentiated tumors, presence of lymphatic invasion and absence of metastasis was more frequently observed in tumors with mutated Kras and/or methylated RASSF1A, FHIT and MGMT genes.ConclusionSynergistic interrelationship between these genes in sporadic CRC may be used as diagnostic/prognostic markers in assessing the overall pathological status of CRC.

Gene promoter methylation in colorectal cancer and healthy adjacent mucosa specimens

“…35 Also in this case, RASSF1A methylation levels varied with studies ranging from 10-20% of CRC subjects up to 40-50%, with some authors observing RASSF1A methylation in early stages of CRC, and others reporting it more frequently methylated in later stages. [35][36][37] Some correlations with tumor stage were also observed in the present study.…”

Lifestyle and Sporadic Colorectal Cancer in India

“…Risk factors including red and processed meat consumption, obesity, physical inactivity, excessive smoking and alcohol consumption may significantly manipulate the causation of CRC (Giovannucci et al, 1995;Boyle et al, 2011;Jemal et al, 2011;Kim et al, 2011;Sinha et al, 2013). In our study, intake of fatty diet (60%), spicy food (45%) and non vegetarian diet (43%) were the most commonly observed lifestyle factors.…”

“…At the molecular level, studies have clearly shown that genetic/ epigenetic changes may greatly affect the development of the disease transforming the epithelial cells into adenocarcinomas (Frank et al, 2010;Carvalho et al, 2012;Sinha et al, 2013;Farkas et al, 2014). Numerous signs and symptoms have been reported in patients presenting with CRC and a host of attributable factors have been found to play a significant role in the development of this disease.…”

“…Rupal Sinha 1,3,5 , Dinesh Chandra Doval 2 *, Showket Hussain 3 , Kapil Kumar 4 , Shivendra Singh 4 , Seemi Farhat Basir 5 , Mausumi Bharadwaj 3 * epithelial cells into adenocarcinomas (Sinha et al, 2013). Patients need to be managed differently depending upon a range of factors including the tumor profile, general physical condition, performance status, etc.…”

The Hippo pathway in colorectal cancer

“…Therefore, expression studies of Hippo pathway components in CRC have been reported by some groups [78,[82][83][84][85][86], however, only Liang et al presented complex data regarding collaborative expression analysis of the most important Hippo genes [87]. They found decreased mRNA ratios of LATS1 and MST1/2 as well as increased mRNA levels of YAP, TAZ, TEAD and OCT4 in CRC in comparison to healthy colon [87].…”