Table 1 Mutation frequencies of pS189 shuttle vector plasmid in NHOK, HPV-immortalized HOK (HOK-16B, HOK-18A, and HOK-18C), and SCC-4 cells*

Table 1. Mutation frequencies of pS189 shuttle vector plasmid in NHOK, HPV-immortalized HOK (HOK-16B, HOK-18A, and HOK-18C), and SCC-4 cells*.

Host Cells	Concentration of MNNG(mg/ml)	Plasmid Recovered # of Mutants/# of Total Colonies	Mutagenesis Frequency (%)
NHOK	0	8/16,785	0.047
NHOK	0.5	14/14,750	0.095
NHOK	1.5	27/15,048	0.179
HOK-16B	0	18/16,872	0.107^†
HOK-16B	0.5	71/20,534	0.346^††
HOK-16B	1.5	85/15,187	0.560^†††
HOK-18A	0	40/22,538	0.178^†
HOK-18A	0.5	121/21,080	0.574^††
HOK-18A	1.5	146/16,631	0.878^†††
HOK-18C	0	23/15,880	0.150^†
HOK-18C	0.5	102/18,078	0.546^††
HOK-18C	1.5	111/15,080	0.736^†††
SCC-4	0	112/18,003	0.622^†
SCC-4	0.5	134/18,930	0.708^††
SCC-4	1.5	140/15,098	0.927^†††

^†Significantly higher than the mutation frequency in unexposed NHOK (Fisher’s exact test, double tail).

^††Significantly higher than the mutation frequency in NHOK exposed to MNNG (0.5 m g/ml) (Fisher’s exact test, double tail).

^†††Significantly higher than the mutation frequency in NHOK exposed to MNNG (1.5 m g/ml) (Fisher’s exact test, double tail).

^*published in Shin et al., 1996.