KRAS Mutation in Small Cell Lung Carcinoma and Extrapulmonary Small Cell Cancer.
BACKGROUND
Lung cancer is one of the most lethal cancers. It is mainly classified into 2 groups: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Extrapulmonary small cell carcinomas (EPSCC) are very rare. The Ras oncogene controls most of the cellular functions in the cell. Overall, 21.6% of human cancers contain a Kirsten Ras (KRAS) mutation. SCLC and EPSCC have several similar features but their clinical course is different.


OBJECTIVE
We investigated the KRAS mutation status in SCLC and EPSCC.


METHODS
Mutation research.


METHODS
Thirty-seven SCLC and 15 EPSCC patients were included in the study. The pathological diagnoses were confirmed by a second pathologist. KRAS analysis was performed in our medical genetic department. DNA isolation was performed with primary tumor tissue using the QIAamp DNA FFPE Tissue kit (Qiagen; Hilden, Germany) in all patients. The therascreen KRAS Pyro Kit 24 V1 (Qiagen; Hilden, Germany) was used for KRAS analyses.


RESULTS
Thirty-four (91.9%) of the SCLC patients were male, while 11 (73.3%) of the EPSCC l patients were female. SCLC was more common in males, and EPSCC in females (p=0.001). A KRAS mutation was found in 6 (16.2%) if SCLC patients. The most common mutation was Q61R (CAA>CGA). Among the 15 EPSCC patients, 2 had a KRAS mutation (13.3%). When KRAS mutant and wild type patients were compared in the SCLC group, no difference was found for overall survival (p=0.6).


CONCLUSIONS
In previous studies, the incidence of KRAS mutation in SCLC was 1-3%; however, it was 16.2% in our study. Therefore, there may be ethnic and geographical differences in the KRAS mutations of SCLC. As a result, KRAS mutation should not be excluded in SCLC.
Department of Medical Oncology, Trakya University School of Medicine, Edirne, Turkey.
Hilmi
H
Kodaz
Department of Medical Pathology, Trakya University School of Medicine, Edirne, Turkey.
Ebru
E
Taştekin
Department of Medical Oncology, Trakya University School of Medicine, Edirne, Turkey.
Bülent
B
Erdoğan
Department of Medical Oncology, Trakya University School of Medicine, Edirne, Turkey.
İlhan
İ
Hacıbekiroğlu
Department of Medical Genetics, Trakya University School of Medicine, Edirne, Turkey.
Hilmi
H
Tozkır
Department of Medical Genetics, Trakya University School of Medicine, Edirne, Turkey.
Hakan
H
Gürkan
Department of Medical Oncology, Trakya University School of Medicine, Edirne, Turkey.
Esma
E
Türkmen
Department of Medical Genetics, Trakya University School of Medicine, Edirne, Turkey.
Bora
B
Demirkan
Department of Medical Oncology, Trakya University School of Medicine, Edirne, Turkey.
Sernaz
S
Uzunoğlu
Department of Medical Oncology, Trakya University School of Medicine, Edirne, Turkey.
İrfan
İ
Çiçin
KRAS mutation; Small cell lung cancer; extrapulmonary small cell carcinoma