The expression of Ki-67 and SF-1 in canine cortisol-secreting adrenocortical tumors

Abstract

The physical and biochemical changes that result from prolonged exposure to increased circulating glucocorticoid concentrations is called hypercortisolism, also known as Cushing’s syndrome. In most ACTH-independent cases of canine hypercortisolism, cortisol-secreting adrenocortical tumors are the source. These tumors can be divided into adenomas or carcinomas according to histology. Unfortunately none of these methods can consistently differentiate between benign and malignant tumors. Therefore, it is needed to integrate the gained information by diagnostic imaging with histological evaluation of the tumor. In human medicine a scoring system has been introduced to improve the reliability of the differential diagnosis of AT. The system is based not only on the results of histopathological examination but also the clinical picture and follow-up. Immunohistochemical staining of Ki-67 and SF-1 are suggested to be diagnostic and perhaps also prognostic markers. In our current study, in none of the adrenal sections positive Ki-67 staining has been detected. Therefore, a new protocol has to be established. Two different SF-1 staining patterns are observed: nucleo-cytoplasmic and purely cytoplasmic. The meaning of this is not clear yet. In conclusion, our study was limited and should be expanded in the future to find out how Ki-67 and SF-1 could function as a diagnostic marker and perhaps also as a prognostic factor. Therefore patient follow up will be very important in combination with expanding the number of cortisol-secreting adrenocorticaltumors.