KIT exon 11 codon 557/558 deletion/insertion mutations define a subset of gastrointestinal stromal tumors with malignant potential

Table 3 Clinicopathological data of GIST patients according to the presence of codon 557/558 deletion/insertion mutations

Variable	Wt (%)	557/558 mutations (%)	Non 557/558 mutations (%)	P
Age (yr)	61.7	67.2	62.5	NS
Size (cm)	8.2	11.3	4.4	0.025
Mitoses
Low ( ≤ 5/50 HPF)	71.4	50	87.5	NS
Intermediate	21.4	37.5	12.5
5-10/50 HPF
High (> 10/50 HPF)	7.1	12.5
Differentiation
Epithelioid	7.1	25		NS
Spindle cell	57.1	50	100
Mixed type 1	14.3	25
Mixed type 2	21.4
Risk assessment
Benign			25	0.003
Very low malignant potential	57.1		12.5
Low malignant potential	7.1	12.5	37.5
Low moderate malignant potential	14.3
Malignant potential	21.4	87.5	25