miRNA expression profile in 3 sporadic young-onset and 2 late-onset Indian colorectal carcinoma patients

Early-Onset Colorectal Carcinoma (EOCRC) is a growing concern as reports indicate a worldwide increase in the incidence of CRC among young adults (<50 years old). In an effort to understand the different mode of pathogenesis in young-onset CRC, we performed a pilot study wherein we looked at colorectal tumors from both young (< 50 years old) and old patients (>55 years old) and screened them to eliminate tumors positive for Microsatellite Instability (MSI) and showing activation of the Wnt pathway, known canonical factors in CRC pathogenesis. RNA isolated from 3 EOCRC and 2 Late-Onset (LOCRC) tumors and paired normal tissues without MSI, nuclear ß-catenin and APC mutations were sent for small RNA seq to identify miRNA alterations between the two subsets. Comparative analysis revealed differential expression of 23 miRNAs specific to EOCRC and 11 miRNAs specific to LOCRC. Overall design: To investigate differential expression of miRNAs between young-onset and late-onset Indian colorectal carcinoma patients, we chose patients with microsatellite stable tumors (MSS) negative for Wnt pathway activation, as detected by absence of nuclear ß-catenin and any APC mutations in the MCR region. These are known canonical factors in CRC pathogenesis and we screened tumors to enable detection of novel oncogenic pathways. Tumours and paired normal tissues of 5 (Patient no. 1, 2, 3, 4 and 5) patients were sent for NGS based miRNA sequencing. The 5 patients which were chosen for miRNA seq consisted of 3 young patients (mean age: 43 years) and 2 old patients (mean age: 63 years). Total twenty paired end fastq files were used for the small RNA-seq analysis via a pipeline FastQC-Fastp-SortMeRNA-miRDeep2-edgeR.