Abstract
Colorectal cancer (CRC) with CpG island methylator phenotype (CIMP) is recognized as a subgroup of CRC that shows association with particular genetic defects and patient outcomes. We analyzed CIMP status of 229 individuals with CRC using an eight-marker panel (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1); CIMP-(+) tumors were defined as having ≥ 5 methylated markers. Patients were divided into individuals who developed a “unique” CRC, which were subclassified into early-onset CRC (EOCRC) and late-onset CRC (LOCRC), and patients with multiple primary CRCs subclassified into synchronous CRC (SCRC) and metachronous CRC (MCRC). We found 9 (15.2%) CIMP-(+) EOCRC patients related with the proximal colon (p = 0.008), and 19 (26.8%) CIMP-(+) LOCRC patients associated with tumor differentiation (p = 0.045), MSI status (p = 0.021) and BRAF mutation (p = 0.001). Thirty-five (64.8%) SCRC patients had at least one CIMP-(+) tumor and 20 (44.4%) MCRC patients presented their first tumor as CIMP-(+). Thirty-nine (72.2%) SCRC patients showed concordant CIMP status in their simultaneous tumors. The differences in CIMP-(+) frequency between groups may reflect the importance of taking into account several criteria for the development of multiple primary neoplasms. Additionally, the concordance between synchronous tumors suggests CIMP status is generally maintained in SCRC patients.
Highlights
Www.nature.com/scientificreports pathways are widely accepted to be involved in the etiology of CRC: Chromosomal Instability (CIN), Microsatellite Instability (MSI) and CpG Island Methylator Phenotype (CIMP)[5,6,7]
We examined CIMP status in different CRC subtypes: patients with a single tumor (“unique” CRC), divided into early-onset CRC (EOCRC; age at diagnosis ≤ 45 years old) and patients with late-onset CRC (LOCRC; age at diagnosis > 70 years old); and individuals diagnosed with multiple primary CRC, i.e. patients diagnosed with Synchronous CRC (SCRC) or metachronous CRC (MCRC)
Among the 59 patients with EOCRC, 8 (13.6%) patients showed MSI status, of www.nature.com/scientificreports which 3 (37.5%) were sporadic cases: 1 (12.5%) presented a BRAF mutation and 2 (25.0%) showed hypermethylation of the MLH1 gene promoter; the remaining 5 (62.5%) individuals were diagnosed with Lynch Syndrome (LS)
Summary
Www.nature.com/scientificreports pathways are widely accepted to be involved in the etiology of CRC: Chromosomal Instability (CIN), Microsatellite Instability (MSI) and CpG Island Methylator Phenotype (CIMP)[5,6,7]. Given the above, when focusing on CIMP status, it is important to take the type of CRC, into consideration, since CIMP status affects the response to therapy[21,22] and it may have a relation to the “field effect” linked to CRC23,24 For this reason, we examined CIMP status in different CRC subtypes: patients with a single tumor (“unique” CRC), divided into early-onset CRC (EOCRC; age at diagnosis ≤ 45 years old) and patients with late-onset CRC (LOCRC; age at diagnosis > 70 years old); and individuals diagnosed with multiple primary CRC, i.e. patients diagnosed with SCRC or MCRC
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