Copy number analysis was also performed, with the previously identified amplifications in HER2 and EGFR being identified, as well as novel amplifications in PIK3CA and FOXA1 and deletions in RB1 and PTEN. A striking finding throughout the study was the detection of genetic heterogeneity both within tumours and between samples, highlighting the diverse nature of this disease. Here, RB1 is linked to neoplasm.