TABLE 1.   Tumorigenic properties of PA-1 cells 

Cell line Growth in nude mice Latent period (wks) 

Clone 1-neo 0/3a >24 
Clone 1-AP-2 2/5b 22, 26 
Clone 1-AP-2 5/6a 16 
Clone 1-GAL4-AP-2 5/7a 8-20 
Clone 1-GAL4-VP16 2/5b 4, 6 
9113 4/4
9113-zeo-PC4c 0/2a >32

a Number of cell lines developed from independently picked G418r colonies that formed tumors in nude mice/total number of cell lines tested. G418r colony-derived cell lines were shown to express the transgenes by reverse transcription-PCR. 
b Pool of transfected G418r colonies: number of mice bearing tumors/number of mice injected with cells. 
c Cell lines 9113-zeo-PC4-1 and 9113-zeo-PC4-2. Note that neither of these 9113-zeo-PC4 clones expressing the PC4 cDNA could form tumors in nude mice.