GP5+/GP6+ PCR for HPV. Human anal squamous genomic DNA samples were tested for the presence of HPV DNA. Hela, CaSki, and SiHa cells are all HPV positive cervical cancer controls. The "+" indicates positive samples, and the "-" indicates negative samples for HPV amplification in the upper panel. The lower panel demonstrates actin as an amplification control of the same samples. The leftmost lane contains a 100 base pair ladder marker. NEG demarcates a negative control without sample DNA.