Abstract:
Objective This study compares the differences of KRAS and epidermal growth factor receptor(EGFR) gene statuses between primary non-small cell lung cancer(NSCLC) and lung cancer with local nodal metastasis.
Methods The mutation of KRAS and EGFR between primary tumors and local lymph node metastases in 80 Chinese NSCLC patients were analyzed using direct sequencing and real-time polymerase chain reaction(RT-PCR), respectively.Five patients were given gefitinib as neoadjuvant therapy after the EG FR-tyrosene kinase inhibitor(TKI) sensitive mutations were detected in their metastasized mediastinal lymph node biopsy.McNemar's test was then used to compare the EGFR and KRAS mutation statuses between primary tumors and homologous local lymph node metastases. Data evaluation was carried out using SPSS-13.0 statistical software.
Results Among the 160 samples, 1 case with primary tumor and 7 metastases were identified with KRAS mutations, whereas 21 primary tumors and 26 metastases were recognized with EGFR mutations. The KRAS and EGFR mutation statuses were different between the primary tumors and the corresponding metastases that occurred in 6 (7.5%) and 7(8.75%) patients, respectively.Moreover, consistent results were obtained through direct sequencing and RT-PCR.Among the five patients who received targeted therapy, primary tumor disease progression was observed in the patient with no TKI-sensitive mutations.
Conclusion Our results show a discrepancy in KRAS and EGFR mutation statuses between primary tumors and corresponding metastases in the small number of Chinese NSCLC patients tested.This observation may have important implication for the use of targeted TKI therapy in treating NSCLC patients.Moreover, RT-PCR is more convenient for clinical examination compared with direct sequencing.