The correlation between serum levels of all MMPs and TIMPs detected and the different variables was investigated, including patient‐dependent variables (age and menopausal status), tumour biology‐dependent variables (classification based on hormones, differentiation grade, positive or negative E‐cadherin and p53, Ki67 percentage and sentinel lymph node involvement) and RT‐related variables (RT regimen, lymph node RT and presence of radiotoxicity). The gene discussed is CDH1; the disease is neoplasm.