Kirsten rat sarcoma virus protein overexpression in adenocarcinoma lung: Association with clinicopathological and histomorphological features.

CONTEXT

Lung cancer is the leading cause of cancer-related deaths worldwide. The constitutive activation of multiple signaling pathways is the major cause of carcinogenesis.

AIMS

The study evaluates the frequency of Kirsten rat sarcoma virus (KRAS) protein overexpression and correlates with clinicopathological and histomorphological features in non-small cell lung carcinoma (NSCLC)-adenocarcinoma.

SETTINGS AND DESIGN

Tertiary hospital-based retrospective and prospective case series included 100 cases of NSCLC-adenocarcinoma.

MATERIALS AND METHODS

The basic panel of Immunohistochemistry including Napsin-A, thyroid transcription factor-1 (TTF-1), and markers for squamous differentiation, p-40 was used in formalin-fixed paraffin-embedded tissue blocks. The KRAS monoclonal antibody (9.13, Thermo Fisher Scientific, USA) was used.

STATISTICAL ANALYSIS USED

The IBM-Statistical Package for the Social Sciences (SPSS) (SPSS, International Business Machines Corporation, New York, NY, USA) analysis software, version 16 was used for all statistical calculations.

RESULTS

KRAS protein expressed in 28.0% (28/100) cases. Cases were grouped as KRAS positive and negative. TTF-1 and Napsin-A were expressed in 89.25% ( = 25) and 92.86% ( = 26) cases, respectively. Stage IV clinical disease was identified in 55% of cases, and 36.84% of cases had a mean survival between 6 and 12 months. In KRAS positive group, the most common pattern of cellular arrangement was acinar/loose clusters pattern present in 64.29% ( = 21) and 75.0% ( = 18) cases followed by the solid pattern present in 42.86% of cases ( = 12), respectively. Necrosis was identified in 57.14% ( = 16) cases. Mucin pattern was present in 32.14% of cases ( = 9), which was significantly different when compared with the KRAS negative group ( = 0.036).

CONCLUSIONS

This finding may imply that KRAS mutations may not be entirely triggered by alterations induced by carcinogens in smoke. KRAS gene is frequently mutated in pulmonary tumors. It should be tested in NSCLC owing to its predictive and prognostic effects.