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

Abstract

母犬的乳腺腫瘤（mammary gland tumor, MGT）為臨床上最常見的腫瘤之ㄧ，其中約有40~50％為惡性腫瘤。術後腫瘤的復發及轉移一直是造成病犬死亡的重要原因，然而，現今獸醫臨床上的診斷工具對於腫瘤復發或轉移的早期並不敏感，容易對於患犬的病情造成誤判。基質金屬蛋白酵素（matrix metalloproteinase, MMP）為一群可分解細胞外基質（extracellular matrix, ECM）成份的酵素，它們對於ECM的分解被認為與腫瘤的侵入及轉移相關。糖皮質固醇（glucocorticoids, GC）在乳腺的發育及分化上扮演著重要的角色，而其也可能參與了乳腺的腫瘤化過程。為了了解MMP-2、MMP-9及GC在乳腺腫瘤犬隻之變化情形，我們收集了經中興大學獸醫教學醫院小動物外科門診診斷為MGT的病例，以gelatin zymography分析MMP-2與MMP-9在腫瘤組織、周圍正常乳腺組織及血漿樣本中活性的變化情形，並以enzyme linked fluorescent assay分析GC在腫瘤組織及周圍正常乳腺組織中濃度的變化。從實驗結果中發現，MMP-2與MMP-9活性在腫瘤組織中皆顯著的高於周圍正常組織，血漿MMP-2與MMP-9活性於MGT病犬也皆顯著高於非腫瘤對照組。血漿MMP-9活性會隨著乳腺腫瘤的移除而下降，但MMP-2並沒有相同的趨勢。在進一步的分析中，血漿MMP-9活性的變化與腫瘤組織中MMP-9活性呈正相關。在GC濃度的分析方面，腫瘤組織及正常乳腺組織間並沒有顯著性差異。根據以上結果，我們發現病犬體內MMP-2與MMP-9活性的變化與腫瘤的惡性程度相關，而血漿MMP-9活性的變化有潛力成為患犬術後病情追蹤及預後評估的指標因子。

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.