Fig. 1

Gel picture of amplicons obtained after nested polymerase chain reaction with two pairs of primers—outer (PGMY09/PGMY11) and inner (GP5+/GP6+, both Genomed) for the detection of human papilloma virus. Both PCR were carried out using 3 μl of the DNA template and amplicons, the final products were separated electrophoretically in 2% agarose gel and visualized using SimplySafe dye (EURx, Poland). Line 1: molecular marker, line PC: positive control (DNA from HPV16-positive squamous cell carcinoma of cervix extracted from cancer tissue obtained from biopsy before cancer treatment, size of the band—150 bp, line NC: negative control (water instead of DNA), lines 1–12: samples of breast cancer. Arrow indicates HPV-positive sample of breast cancer (sample code 561,482, size of the band—150 bp). The light bands in negative lanes most likely come from highly degraded DNA extracted from FFPE tissues. Genomic DNA extracted from FFPE tissues is highly degraded due to the cross-linking between nucleic acid strands and proteins, as well as random breakings in sequence