In the tumour of the left eye, the remaining copy of RB1 was lost via a large somatic deletion encompassing most of chromosome 13q, resulting in LOH of RB1. A substantially greater number of mutations was detected including 931 substitutions, 103 small indels, 5 rearrangements, gains on chromosomes 3q, 6p, 14q, 12p and 12q and two deletions on chromosomes 17 and X. None of the somatic mutations were shared between the tumours from the two eyes, confirming that the two tumours had arisen independently. Here, RB1 is linked to neoplasm.