Ricerc@Sapienza

Background/aim: Matrix metalloproteinase 7 (MMP7) expression is highly associated with colorectal cancer and modulates tumour growth and invasion. Radiation injury induces inflammation with increases in MMP7 and in transforming growth factor beta (TGF?). The aim of this study was to investigate the effect on MMP7 and TGF?. expression in patients with rectal cancer undergoing different regimens of neoadjuvant radiotherapy (RT).

Patients and methods: We studied 53 patients in three RT treatment groups receiving RT of 25 Gy, long-term RT 50 Gy and controls receiving no RT. Three biopsies were obtained from each patient during the treatments: before RT, after RT and after surgery. Tissue samples were formalin fixed, paraffin embedded and tissue microarrays were constructed and stained for MMP7 and TGF?. Mann-Whitney U-tests and Wilcoxon Z-tests were used to determine differences between patients before and after RT, and after surgery, as well as between the RT groups.

Results: In all three patient groups, increases of MMP7 and TGF? expression were observed after surgery. MMP7 expression was significantly increased in patients receiving short-term RT but TGF? expression was not affected by RT.

Conclusion: 50 Gy Irradiation of rectal cancer gives less tumour activation of MMP7, whilst it is up-regulated by 25 Gy and surgery regardless of RT.