Histopathological features with anaplastic lymphoma kinase and epidermal growth factor receptor expression of brain metastases from lung adenocarcinoma.

Objective To analyze the clinical-pathological features of brain metastases of lung adenocarcinoma and detect the expressions of anaplastic lymphoma kinase (ALK) and epidermal growth factor receptor (EGFR) in order to guide the targeted drug therapy of patients with advanced lung cancer. Methods A total of 86 cases of brain metastases from non-small cell lung cancer (NSCLC) in Huashan Hospital, Fudan University from January 2013 to December 2016 were selected for pathological analysis by HE staining and immunolabeling, ALK and EGFR expression were detected by immunohistochemical staining. Results Among 86 cases of brain metastases from NSCLC, 74 cases (86.05%) were adenocarcinoma, 3 cases (3.49%) of squamous cell carcinoma, and 9 cases (10.47%) of neuroendocrine tumors. Among the 74 brain metastases from lung adenocarcinoma, there were 44 cases (59.46%) of solid type, 9 cases (12.16%) of acinar type, 14 cases (18.42%) of papillary type and 7 cases (9.46%) of micropapillary type, which were significantly different from the pathological subtypes of primary lung adenocarcinoma reported in the literature (χ² = 97.858, P = 0.000). The expression rate of ALK protein was 9.46% (7/74), the expression rates were not statistically significant in different pathological types (χ² = 1.690, P = 0.639). The expression rate of EGFR non-mutant protein was 52.70% (39/74), and the expression rates were statistically significant in different pathological types (χ² = 7.938, P = 0.047). Fourteen cases (18.92%, 14/74) showed positive staining by specific mutation antibody of exon 19 of EGFR gene, while 12 cases (16.22%, 12/74) having exon 21 of EGFR gene mutation, and the total positive rate was 33.78% (25/74), the expression rates were not statistically significant in different pathological types (χ² = 1.721, P = 0.632). The expression levels of ALK and EGFR in brain metastases from lung adenocarcinoma were mutually exclusive (χ² = 12.462, P = 0.001). Conclusions Among lung adenocarcinoma, the solid lung type and the micropapillary type have higher tendencies of brain metastasis. The expression rates of ALK and EGFR in brain metastases were consistent with those of primary lung adenocarcinoma, and their expression was mutually exclusive. [ABSTRACT FROM AUTHOR]