Table 2. HD selection pressure and small deletion rate across 746 cancer cell lines.

Locus	Class	Small hemizygous deletions	HDs	HD selection pressure (λ)	Small deletion rate (${\stackrel{‒}{\mathcal{p}}}_s$,%)
PTEN	RCG	2	29	13.0	0.4
RB1	RCG	1	16	10.2	0.2
TGFBR2	Unexplained	0	8	9.8	0.1
CDKN2A	RCG	11	195	8.3	1.9
MAP2K4	RCG	0	8	8.3	0.1
SMAD4	RCG	3	17	6.1	0.4
CDKN2C	Unexplained	4	13	5.7	0.5
NF1	RCG	3	7	3.2	0.4
Chr 11 (80 Mb)	Unexplained	4	6	2.9	0.4
CTNNA1	Unexplained	4	7	2.6	0.5
Chr 21 (17 Mb)	Unexplained	1	6	2.3	0.0
Chr 13 (57 Mb)	Unexplained	2	7	2.3	0.1
FRA2F	FRA	32	24	2.0	3.2
FRA7K	FRA	13	9	1.8	1.3
Chr 16 (6Mb)	Unexplained	17	13	1.8	1.7
Chr 20 (15 Mb)	Unexplained	40	29	1.8	4.3
FRA3B	FRA	34	51	1.6	4.5
FRA6E	FRA	11	11	1.6	1.2
Chr 1 (72 Mb)	Unexplained	9	6	1.6	0.9
FRA4F	FRA	19	12	1.1	2.1
Chr 3 (118 Mb)	Unexplained	25	11	1.1	2.5
FRA5H	FRA	10	6	1.1	1.0
FRA16D	FRA	49	22	0.8	5.5
PTPRD	Unexplained	21	28	0.7	2.5
Chr 4 (181 Mb)	Unexplained	23	11	0.7	2.4
Chr 8 (5Mb)	Unexplained	14	6	0.6	1.5

Homozygous and small hemizygous deletion counts (overlapping a 100-kb window) for all HD clusters with six or more HDs at recessive cancer genes (RCG), fragile sites (FRA) or unexplained loci. The HD selection pressure (λ) is determined by comparing the ratio of the homozygous to hemizygous deletions for a cluster against the average ratio over all fragile sites. A change in this ratio represents the relative selection at this cluster. The small deletion rate is estimated from the observed counts and is an indicator of local fragility.