Subgroup analysis among the patients presenting with LCNEC showed that patients with CK7+ results in the immunohistochemical analysis had a significantly worse outcome in terms of mean survival rate (CK7+: 19.23 ± 4.8 months; CK7−: 57.01 ± 8.5 months, p = 0.019). This evidence concerns the gene KRT7 and large cell neuroendocrine carcinoma.