CREB1 and in situ carcinoma: In the nucleus, p38 MAPK α regulates transcription of several targets, and our data showed that in tumors with concomitant CIS the majority of these targets were up regulated, like cAMP responsive element binding protein 1 (CREB1), activating transcription factor 1 and 2 (ATF1, ATF2), MADS box transcription enhancer factor 2, polypeptide A and C (MEF2A, MEF2C), signal transducer and activator of transcription 1 (STAT1), while DNA-damage-inducible transcript 3 (DDIT3 = CHOP) was down regulated.