FAT1 and neoplasm: Notably, mirrored subclonal allelic imbalance (MSAI; where the maternal allele is gained or lost in one subclone of a tumour, but the paternal allele is gained or lost in another independently) was identified at two genomic loci: part of chromosome 4q (containing the tumour suppressor FAT1) and a focal segment on the p arm of chromosome 2 (Fig. 4C, D).