基質金屬蛋白酵素-2、-9與糖皮質固醇於乳腺腫瘤犬隻之變化

Mammary gland tumor (MGT) is one of the most common neoplasias in female dogs, having approximately 40~50% of them considered malignant. Tumor recurrence and metastasis are the most important factors to cause patient death after surgery. However, the diagnostic tools in veterinary practice up to now are not sensitive in early stage of tumor recurrence and metastasis. Matrix metalloproteinase (MMP) family is thought to be responsible for the accelerated breakdown of extra-cellular matrix (ECM) associated with tumor invasion and metastasis. Besides, glucocorticoids (GC) has been shown to play important roles in mammary development and differentiation, and probably implicated in mammary tumorigenesis. In order to understand the change of MMP-2, MMP-9 and GC in dogs with MGT, the activity of MMP-2 and MMP-9 in plasma samples, MGT tissues and normal mammary gland tissues near by were evaluated by gelatin zymography, and the concentration of GC in MGT tissues and normal mammary gland tissues near by was determined by enzyme linked fluorescent assay. The levels of MMP-2 and MMP-9 were significantly higher in tumor tissues than those in normal gland tissues. Plasma MMP-9 levels in malignant cases were higher than that in benign and nontumor cases. Likewise, plasma MMP-2 levels in most MGT cases were higher than nontumor cases. The level of plasma MMP-9 decreased after surgery, but MMP-2 did not. Further analysis indicated that plasma MMP-9 levels were correlated with tumor tissue MMP-9 levels. GC concentration in MGT tissues has no significantly difference from normal gland tissues. Our results indicated that the change of MMP-2 and MMP-9 levels are associated with tumor malignancy, and plasma MMP-9 activity may become a potential marker both in the follow-up and in the prognosis of canine MGT patients.