ALDH1A1 and lung cancer: However, previous studies have found that ALDH1A2 and ALDH1B1 might be major contributors to the ALDH1 activity in non‐small cell lung cancers (NSCLCs) and a high expression of ALDH1A2 mRNA is significantly associated with poorer survival in patients,135 suggesting that ALDH1A2 may play different regulatory roles in different cancers.