Outcomes of standard liquid PCR using HPV primers. 2% agarose gel of Nested PCR products from breast milk samples. M = Puc Hinf 1 size standard (1,419 bp, 517 bp plus 396 bp, 214 bp, 75/65 bp). 1-40 = samples (only 1-16 shown). RB = reagent blank. B1 = no DNA PCR blank after 2 round. B2 = no DNA PCR blank after 1 round. + = positive control (HeLa DNA).