ALK-rearranged squamous cell carcinoma of the lung.

Background: ALK rearrangement is a very rare subset of squamous cell carcinoma (SCC) and one of the clinical features in patients is lack of data. Here, we report eight patients diagnosed with SCC of the lung harboring ALK rearrangement.

Methods: We collected primary NSCLC samples at the Beijing Chest Hospital between January 2012 and December 2018 for Ventana (D5F3) immunohistochemical detection. Among the 148 patients was diagnosed ALK-rearranged non small cell lung cancer (NSCLC), only eight cases was SCC. We collected patients information from electronic patent records (EPRs).

Results: The eight cases of SCC were diagnosed by immunohistochemistry (IHC). Two were given crizotinib as second-line therapy. One patient had stable disease (SD) and progression-free survival (PFS) of six months. The other patient had progressive disease (PD) but PFS was only one month. The side effects were tolerable. This report identified 31 cases of ALK rearrangement in SCC patients from a literature search (including the eight patients in this study). These fusion genes are often seen in a younger age group (mean age: 55.6 years) and non-smokers (18/31, 58.1%). A total of 20 cases received an ALK inhibitor as first- or second-line treatment which included 11 with a partial response (PR), four with SD, and five with PD. The DCR and ORR was 75.0% (15/20) and 55.0% (11/20), respectively. The median duration time of therapy was 6.4 ± 4.4 months.

Conclusions: Patients with ALK-rearranged SCC obtained clinical benefit from ALK-inhibitor therapy, especially those who were non-smokers and whose tumors had been identified by IHC+/FISH+.