[ALK gene fusion associated non-small cell lung cancer: automated immunostainer detection and clinicopathologic perspectives]

To explore the automated immunostainer screening anaplastic lymphoma kinase (ALK) gene fusion non-small cell lung cancer (NSCLC) and clinicopathological characteristics of the molecular subtype lung cancers. Methods Five hundred and sixty-six cases of NSCLC were collected over a 16 month period. The test for ALK was performed by Ventana automated immunostainer with anti-ALK D5F3. The histological features, treatment and outcome of patients were assessed. Results Thirty-eight cases (6.7%, 38/566) of NSCLC showed ALK gene fusion. The frequency of ALK gene fusion was higher in male (7.1%, 25/350) than that in female (6.0%, 13/216) patients, but not achieving statistical significance (chi2 = 0.270, P = 0.604). ALK + NSCLC was more significantly more frequent in patients < or = 60 years (9.9%, 28/282) than >60 years (3.5% , 10/284) of age. Histologically, the ALK + NSCLCs were mostly adenocarcinoma (81.6%, 31/38) , among which eighteen cases were solid predominant subtype with mucin production; nine cases were acinar predominant subtype; one case was papillary predominant subtype and three cases were invasive mucinous adenocarcinoma. The ALK + non-adenocarcinoma included three cases of squamous cell carcinoma, three cases of adenosquamous carcinoma and one case of pleomorphic carcinoma. Among the ALK + NSCLC patients, the number of non/light cigarette smokers (86. 8% , 33/38) was more than that of heavy smokers. Twenty-nine cases were stages III and IV; twenty-nine cases showed lymph node metastasis; twenty cases showed metastases mostly to brain and bone; and one case showed EGFR gene mutation coexisting with ALK gene fusion. Twelve of fifteen patients received crizotinib therapy and remained stable. Conclusions NSCLC with ALK gene rearrangement shows distinctive clinical and histological features. Ventana-IHC may he a feasible and valid technique for detection of ALK rearrangement in NSCLC.