Extraordinary response to crizotinib in a woman with squamous cell lung cancer after two courses of failed chemotherapy

BACKGROUND: The discovery of the fusion gene echinodermmicro tubule associated proteinlike 4-anaplastic lymphoma kinase, EML4-ALK, in patients with non-small-cell lung cancer has led to the remarkable development of anaplastic lymphoma kinase inhibitors, such as crizotinib. Consequently, the clinical outcomes of these patients have improved dramatically. Herein, we report the case of a woman with ALK gene translocation-squamous cell lung cancer who experienced a remarkable tumor response to crizotinib after two courses of failed chemotherapy. CASE PRESENTATION: A 55-year-old Chinese woman was diagnosed with cervical lymph node metastatic squamous carcinoma. Chest computed tomography scan showed the primary tumor in the lower lobe of the right lung. The patient had received two successive courses of first-line chemotherapy without tumor response. Tumor cells were negative for wild-type of epidermal growth factor receptor/K-RAS variants; thus, she was not eligible for tyrosine kinase inhibitor therapy. Unfortunately, increased levels of interleukin-6 and carcinoembryonic antigen, and computed tomography scan results indicated cancer progression. Once crizotinib was approved by the China Food and Drug Administration and the ALK gene translocation was identified in tumor cells by fluorescent in situ hybridization, the patient commenced treatment with crizotinib. Remarkably, the tumor response to crizotinib was classified as partial response after only 26 days of treatment commencement. The partial response status has been maintained to date (23 weeks). CONCLUSION: Considering this remarkable response to crizotinib, we can safely conclude that patients with squamous cell lung cancer should have the option of undergoing ALK testing to determine if there is indication for crizotinib treatment even after they have failed chemotherapy.