BHLHA15 and neoplasm: We chose to focus on two key pancreas bHLH factors (MIST1 and PTF1a) because (i) MIST1 and PTF1a are silenced in KRAS‐expressing acinar cells, (ii) their silencing promotes the progression of precancerous lesions (Krah et al., 2015; Shi et al., 2009), and (iii) forced expression of MIST1 in the context of KRAS signaling mitigates the effects of silencing the endogenous alleles on PDAC formation (Shi et al., 2013), suggesting that these bHLH factors function as tumor suppressors.