Table 2.

OD of the four groups of A375 cells following culture for 12, 24, 48, 56, and 68 h

	Optical density
	0 h	12 h	24 h	48 h	56 h	68 h
Group 1	0.312	0.391	0.560	0.721	0.874	0.977
Group 2	0.309	0.387	0.553	0.704	0.859	0.960
Group 3	0.319	0.409	0.607	0.814	0.997	1.136
Group 4	0.309	0.377	0.514	0.623	0.737	0.812
P1vs2	0.798	0.898	0.824	0.717	0.841	0.937
P1vs3	0.174	0.041	0.005	0.003	0.002	0.007
P1vs4	0.734	0.136	0.005	0.002	0.001	0.005

Statistical difference was analyzed with the paired-samples t-test from 12 h to 68 h. The OD value of the A375/H19⁺ cells was higher than that of the A375/GFP, A375, and A375/H19^- cells after culturing for 12 h (P < 0.05), and the difference was more apparent with longer culture times (P < 0.01 for 24, 48, 56, and 68 h).