Comparison of MMP-2, MMP-9, COX-2, and PGP Expression in Feline Injection-Site and Feline Noninjection-Site Sarcomas-Pilot Study

Abstract

Feline injection-site sarcomas (FISSs) are aggressive neoplasms that have been associated mostly with vaccination. Feline noninjection-site sarcomas (non-FISSs) are less frequently observed in cats and may arise in any anatomic site. This study aimed to determine the differences in the expression of the selected proteins (matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), cyclooxygenase-2 (COX-2), and P-glycoprotein (PGP)) and their correlation with the mitotic count in FISS and non-FISS, in order to characterize their immunohistochemical features. A preliminary study of eleven samples of FISS and eight samples of non-FISS was performed using immunohistochemistry. Among all the tested sarcomas, 80.4% of the tumors were positive for COX-2, 90.2% were positive for MMP-9, and 100% were positive for PGP. The results showed that the expressions of COX-2, MMP-9, and PGP were significantly higher in FISS than in non-FISS (COX-2-p ≤ 0.001; MMP-9-p ≤ 0.05; and PGP-p ≤ 0.05). A Spearman rank correlation analysis showed a moderate negative correlation between the expression of COX-2 and MMP-9 in FISS (r = -0.52). A strong negative correlation between COX-2 and PGP (r = -0.81), a moderate positive correlation between MMP-2 and MMP-9 (r = +0.69), and a moderate negative correlation between MMP-2 and PGP (r = -0.44) were observed in non-FISS. In summary, our study presents the immunohistochemical profile of the proteins involved with inflammation and carcinogenesis in FISS and non-FISS, which can contribute to expanding the knowledge of tumor biology.

Keywords: P-glycoprotein; cyclooxygenase-2; feline injection-site sarcoma; fibrosarcoma; immunohistochemistry; matrix metalloprotease.

Figure 1

Localization of COX-2-expressing cells in FISS (A,B) and non-FISS (C,D), immunohistochemically stained. Brown color indicates positive staining. Positive immunostaining for COX-2 in FISS, intensity 3, 90% of positive cells, magnification 20× and 40×, respectively (A,B). Positive immunostaining for COX-2 in non-FISS, intensity 1, 60% of positive cells, magnification 20× and 40×, respectively (C,D).

Figure 2

Statistical analysis of P-glycoprotein (PGP) (a), cyclooxygenase 2 (COX-2) (b), matrix metalloproteinase-2 (MMP-2) (c), and matrix metalloproteinase-9 (MMP-9) (d) expressions in evaluated groups. (a) Significant (*) (p ≤ 0.05) difference in PGP expression with feline injection-site sarcoma (FISS) and with feline noninjection-site sarcoma (non-FISS). (b) Significantly higher (***) (p ≤ 0.001) expression of COX-2 with FISS and non-FISS. (c) No significant difference in MMP-2 expression with FISS and non-FISS. (d) Significantly (*) (p ≤ 0.05) higher expression of MMP-9 with FISS than with non-FISS.

Figure 3

Localization of MMP-2-expressing cells in FISS (A,B) and non-FISS (C,D), immunohistochemically stained. Brown color indicates positive staining. Positive immunostaining for MMP-2 in FISS, intensity 2, 87% of positive cells, magnification 20× and 40×, respectively (A,B). Positive immunostaining for MMP-2 in non-FISS, intensity 1, 90% of positive cells, magnification 20× and 40×, respectively (C,D).

Figure 4

Localization of the MMP-9-expressing cells in FISS (A,B) and non-FISS (C,D), immunohistochemically stained. Brown color indicates positive staining. Positive immunostaining for MMP-9 in FISS, intensity 3, 96% of positive cells, magnification 20× and 40×, respectively (A,B). Positive immunostaining for MMP-9 in non-FISS, intensity 3, 90% of positive cells, magnification 20× and 40×, respectively (C,D).

Figure 5

Localization of PGP-expressing cells in FISS (A,B) and non-FISS (C,D), immunohistochemically stained. Brown color indicates positive staining. Positive immunostaining for PGP in FISS, intensity 3, 100% of positive cells, magnification 20× and 40×, respectively (A,B). Positive immunostaining for PGP in non-FISS, intensity 2, 90% of positive cells, magnification 20× and 40×, respectively (C,D).

Figure 6

Correlation analysis of the malignancy grade and expressions of P-glycoprotein (PGP), cyclooxygenase-2 (COX-2), matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-9 (MMP-9) in feline injection-site sarcoma (FISS) (A) and feline noninjection-site sarcoma (non-FISS) (B). The correlation was analyzed using a Spearman rank correlation analysis.