Droplet digital PCR revealed high concordance between primary tumors and lymph node metastases in multiplex screening of KRAS mutations in colorectal cancer

In this study, we report the application of ddPCR technology in order to analyze the presence ofKRAS mutations in primary tumor and matched metastasis in lymph nodes (LNs) from patients with mCRC and address the question, whether the improvement in the detection method can lower the discrepancies ofKRAS mutations detection between the primary tumor and regional LNs. Genomic DNA with wtKRAS and commercial DNA with mtKRAS (G12D) were used to set up the ddPCR reaction. Formalin-fixed paraffin-embedded tissues from primary tumor and positive lymph node from 31 patients with mCRC were analyzed using ddPCR and Sanger sequencing.KRAS status of primary tumors was known; however, the mutation status of lymph nodes was not detected previously. From 31 samples of primary tumors, our results corresponded to results from IVD kit in 30 cases. For one patient, ddPCR detectedKRAS mutation in comparison with negative result of the IVD kit. In the samples of metastatic infiltrated LNs, ddPCR detected 16 samples as a WTKRAS and 15 lymph nodes showed positivity forKRAS mutation, whereby Sanger sequencing foundKRAS mutations in 8 cases only. We also found two cases where genetic conditions ofKRAS gene differed between primary tumor and infiltrated lymph node, both “low-grade” adenocarcinoma. Our study approved that ddPCR method is adequate technique with high sensitivity and in the future may be used as a diagnostic tool for evaluation ofKRAS mutations, especially in infiltrated LNs of patien...
Source: Clinical and Experimental Medicine - Category: Research Source Type: research