Notably, two cases of ALK-rearranged pure Sq-LC that were negative by IHC (cases 2 and 4) had an extremely short PFS; however, they did not differ in terms of PFS from two cases of ALK-rearranged AdSq-LC (cases 1 and 5) (Figure 4A and Table 2). The gene discussed is ALK; the disease is laryngotracheoesophageal cleft.