CDK4 and non-small cell lung carcinoma: To determine whether a CDKN2A mutation or homologous deletion (found in 38% of our NSCLC PDX panel) can be used as a biomarker of response to a CDK4/6 inhibitor in NSCLC, treatment with palbociclib alone or in combination with chemotherapies was carried out in two ADCs with CDKN2A homologous deletions and two SCCs with CDKN2A mutations (Figure 5a).