Prognostic Factors for Canine Cutaneous Mast Cell Tumors including Ki67, MAC387, Factor 8 and MMP-9 immunohistochemistry

Abstract

Objective– To evaluate the prognosis of canine cutaneous mast cell tumors using immunohistochemical detection of Ki67, MAC387, Factor 8 and MMP-9 and using Patnaik and Kiupel grades and histological information concerning vessel invasion, infiltration of the surrounding tissue, amount of collagen, presence of lymphocytes, amount of edema, ulceration of the skin, location of the tumor, necrosis and flame figures.

Samples–33 mast cell tumors (MCTs) of different grades from 33 dogs submitted from different Dutch veterinary clinics from 2008-2010 to the pathology department of the Faculty of Veterinary Medicine of Utrecht University, The Netherlands. The population consisted of 14 male and 19 female dogs, representing a variety of breeds.

Procedures–The mast cell tumors were histologically graded with Patnaik and Kiupel grading schemes. Additional histologic information was noted concerning vessel invasion, infiltration of the surrounding tissue, amount of collagen, presence of lymphocytes, amount of edema, ulceration of the skin, location of the tumor within the skin, necrosis and flame figures. Ki67, MAC387, Factor 8 and MMP-9 antibodies were used for immunohistochemistry. The relationships between the immunohistochemistry, the histology and the clinical follow-up data were investigated. The clinical data was used to compute overall survival time(OST) and the progression free survival(PFS).

Results– Parameters significantly correlated to the Patnaik and Kiupel grades are: tumor size, degree of tumor excision, vessel invasion, infiltration of the surrounding tissue, lymphocytes, ulceration of the skin, necrosis, flame figures, KI67 and Factor 8(blocks). Significant relationships between the parameters and OST/PFS with the use of the Kaplan-Meier test were found with the parameters: tumor size, vessel invasion, lymphocytes, ulceration, necrosis, flame figures, KI67 and Factor 8(blocks).

Conclusions and clinical relevance– The parameters of tumor size, the amount of excision of the tumor and the presence of vessel invasion, lymphocytes, ulceration and necrosis should be evaluated when histologically examining MCTs. For further evaluation, extra immunohistochemistry for Ki67 and Factor 8 are useful for determining the prognosis for dogs with MCTs.