[Non-small Cell Lung Cancer: HER2 Oncogene Status]

Objective: to study HER2 protein and HER2 gene, their heterogeneity in non-small cell lung cancer.

Material And Methods: 218 intraoperative non-small cell lung samples were examined using tissue matrix methods. HER2 protein was determined by immunohistochemistry (clone 4B5, <<Ventana>> and HER2 gene and CEP1 7 were evaluated by in situ hybridization (SISH, <<Ventana>>).

Results: Positive and indefinite statuses were found in 59 (27%) and 47 (22%) cases, respectively; intratumor heterogeneity was detected in 32 (30%) cases. Amplification of the HER-2 gene was found in 12 (6%) cases; that of the HER2 gene along with an increase in CEPI 7 was observed in 7 (3%) cases; elevated CEP1 7 levels were seen in 19 (9%) cases. Intratumor heterogeneity of HER2 gene amplification was not found; however, one case of adenocarcinoma showed high-level HER2 gene amplification in the gland-like areas and low-level HER2 gene amplification in the solid areas. HER2-positive status and amplification were more common in adenocarcinoma than in squamous cell carcinoma (p<0.001). There was a moderate correlation between HER2 immunohistochemical status and amplification (r=0.38; p<0.001).

Conclusion: Thus, in non-small cell lung cancer, there is an elevated HER2 protein level and, well less frequently, altered activity in the HER2 gene (amplification) as a cause of enhanced protein synthesis.