[1937] EGFR and KRAS Mutation Status in Patients with Non-Small Cell Lung Cancer and Additional Primary Colorectal or Gastric Cancer

Mee Sook Roh, Phil Jo Choi, Choonhee Son. Dong-A University College of Medicine, Busan, Republic of Korea

Background: The molecular analysis of multiple cancers occurring in a single patient may improve understanding of general molecular principles of carcinogenesis. Colorectal cancer (CRC) or gastric cancer (GC) frequently develops as the second primary cancer in Korean non-small cell lung cancer (NSCLC) patients, which might be due in part to a common molecular basis. To determine possible underlying molecular relationships, we analyzed EGFR and KRAS mutation status in patients with NSCLC and additional CRC or GC.
Design: Twenty-eight patients with NSCLC had an occurrence of primary CRC (15 patients) or GC (13 patients) in their history or in the follow-up period. After genomic DNA was extracted from paraffin-embedded tissues, mutation analysis of EGFR gene exons 19 and 21 and KRAS gene codons 12 and 13 were performed using peptide nucleic acid-clamp real-time PCR-based assay in both NSCLCs and their CRCs or GCs.
Results: In 15 NSCLC patients with CRC, the detection rate for EGFR mutation was 40.0% (6 cases: 3 each in exons 19 and 21) of NSCLCs and 13.3% (2 cases: 1 each in exons 19 and 21) of CRCs and that for KRAS mutation was 26.7% (4 cases: all in codon 12) of NSCLCs and 26.7% (4 cases: 3 in codon 12 and 1 in codon 13) of CRCs. Three (20.0%) showed an identical EGFR or KRAS mutation in both NSCLC and CRC: identical EGFR mutation in 2 patients and identical KRAS mutation in 1 patient. In contrast, the detection rate for EGFR mutation was 23.1% (3 cases: 1 in exon 19 and 2 in exon 21) of NSCLCs and 15.4% (2 cases: both in exon 21) of GC in 13 NSCLC patients with GCs. An identical EGFR mutation in both NSCLC and GC was found only 1 patient (7.7%). No KRAS mutation was found in the patients with both NSCLCs and GCs.

Comparison of the EGFR and KRAS mutation status between the non-small cell lung cancers and their additional primary colorectal or gastric cancers
GeneMutation statusCancer
  NSCLC/CRC (n=15,%)NSCLC/GC (n=13,%)
EGFR-/-9 (60.0)9 (69.2)
 -/+0 (0)1 (7.7)
 +/-4 (26.7)2 (15.4)
 +/+2 (13.3)1 (7.7)
KRAS-/-8 (53.3)13 (100)
 -/+3 (20.0)0 (0)
 +/-3 (20.0)0 (0)
 +/+1 (6.7)0 (0)
NSCLC, Non-small cell lung cancer; CRC, Colorectal cancer; GC, Gastric cancer.


Conclusions: We found that EGFR or KRAS mutations may play a certain role in developing NSCLC and concomitant CRC, which may explain the association of the higher incidence of occurrence between the two cancers. Further studies with a large number of cases for other genetic changes leading to a higher susceptibility for cancer may determine why individuals with NSCLC have a higher risk of developing CRC or GC.
Category: Pulmonary

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 293, Tuesday Afternoon

 

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