RT-PCR analysis of MMP-9, MMP-2, TIMP-1, IL-6, IL-10, and TNF- mRNA expression in NHL and tonsil (T). RNA extraction and RT-PCR analysis were performed as described in Materials and Methods. NHL are described (cases 1 to 32) in Materials and Methods. Each analysis was internally controlled by inclusion of GAPDH primers for the last 20 cycles of PCR.