Expression of MMP mRNA in human normal breast and breast cancer tissue analyzed by semiquantitative RT-PCR. Total mRNA from normal breast, breast cancer tissue grade 2 (G2) and breast cancer tissue grade 3 (G3) samples was used as template for RT-PCR analysis. Primers used in PCR reactions were designed in flanking exons, specific for each MMP transcripts (primer sequences are listed in Additional file 2). The gene porphobilinogen deaminase (PBGD) was used as internal loading control and the amount of each cDNA was normalized to the amount of PBGD. Genomic DNA amplified by the primer pair as well served as positive control (+).