In relation to Iida et al., the cohort in this study had more NE marker positivity; this difference may be explained by the different TTF-1 clones used (SPT24 versus 8G7G3/1) [4]. It should be noted that the International Association of Lung Cancer Study (IASLC) has criteria for TTF-1 positivity [14]. It is presumed that these were applied in the routine in-house practice; however, this was not assessed. The gene discussed is TTF1; the disease is lung cancer.