NCAM1 and small cell lung carcinoma: SCLC is the most common form of neuroendocrine lung cancer and produces the classic neuroendocrine markers, Chromogranin A, synaptophysin, NCAM (CD56) and Calcitonin gene-related peptide (CGRP), which are commonly used as SCLC tumor markers (Stovold et al., 2013; Martinez-Pacheco and O’Driscoll, 2021).