Table 1. Correlation between hotspot mutations and the invasion depth.

	LGIN/HGIN	EP	LPM	MM/SM1	P-value
TP53 mutation	6/7 (85%)	15/18 (83%)	18/19 (95%)	8/10 (80%)	0.89
CDKN2A mutation	2/7 (29%)	5/18 (28%)	3/19 (16%)	1/10 (10%)	0.19
TP53 or CDKN2A mutation	6/7 (85%)	16/18 (89%)	18/19 (95%)	9/10 (90%)	0.85
Other mutations	0/7 (0%)	3/18 (17%)	4/19 (21%)	6/10 (60%)	0.01*

Correlation between invasion depth and the mutation rate was calculated by the Cochran-Armitage trend test.