SPI1 and neoplasm: To investigate the role of the transcription factor PU.1 in NSCLC, we collected post-surgery lung tissue samples from the tumoral region (TU), peritumoral region (PT) and tumor-free control region (CTR) of NSCLC patients (Figure 1A). First, we analyzed the expression of PU.1 (SPI1) on mRNA level in the different lung tissue regions.