The RT2-PCR array revealed that compared to untreated cells expression of cylin dependent kinase inhibitor (CDI) genes [CDKN1A (p21), CDKN1B (p27), CDKN1C (p57), CDKN2A (p16) and CDKN2B (p15),] were up regulated in QU + CIS and QU treated cells respectively. This evidence concerns the gene CDKN1B and in situ carcinoma.