MMR deficiency of lung cancer patients.

Abstract

e21523 Background: DNA Mismatch repair (MMR) plays an essential role in the genetic. The main function of MMR is thought to correct post replication errors since the system could recognizes base exchanges and short DNA insertions or deletions. Somatic mutation of MMR are common detected in lung cancer, and several studies has shown that the presence of MMR mutation may be resistance to EGFR-TKI. Here we retrospectively analyzed the MMR mutation in chinese lung cancer. Methods: We retrospectively analyzed the genetic aberration in 910 Chinese lung patients. All the patients were detected by hybridization capture-based NGS 1021-gene panel. Results: Here is an interesting lung cancer case which was called EGFR T790M, TP53 and MSH2 somatic mutations without any germline mutations, and this patient showed no response to Osimertinib. We retrospectively analyzed the MMR in 910 patients and called 39 patients with MMR mutation.The percence of MLH1, MLH2, MSH3, MSH6, PMS1 and PMS2 mutations rate is as followed: 10.3% (4/39), 33.3% (13/39), 7.7% (3/39), 28.2% (11/39), 5.1% (2/39), and 15.4% (6/39) cases in PMS2 mutation. Also we found that TP53 is the most highly concurrent gene for MRR deficiency the rate is 79.5%(31/39). The rate of EGFR mutation concurrent with MMR deficiency is 27% (10/39). Conclusions: MMR deficiency was found in 4.3% chinese lung cancer and 27% of them concurrent with EGFR. [Table: see text] [Table: see text] [Table: see text]