MMP2 and cancer: In summary, although our study has the limitation of being cross-sectional and lacking changes of phenotypic expression with time, it would appear that with androgen blockade there is early selection of HER-2 positive cancer cells; HER-2 activates the androgen receptor through MAPK and/or AKT pathways leading to androgen independence and increased expression of MMP-2 promoter and MMP-2 activity in the micrometastasis through the same pathways.