Читать книгу Veterinary Surgical Oncology - Группа авторов - Страница 118

Indicators of cellular proliferation can provide prognostic information about the likelihood of MCTs recurring locally and help differentiate the prognosis of grade II MCTs (Séguin et al. 2006). The three most commonly used cellular proliferation indices are AgNORs, proliferating cell nuclear antigen (PCNA), and number of Ki67‐positive nuclei. Increasing AgNOR and PCNA scores were significantly associated with a shorter progression free interval (Gill et al. 2007). A Ki67 index of greater than 1.8% is a significantly prognostic indicator for poorer survival for grade II MCTs. A higher Ki67 index is also a negative prognostic factor, independent of grade (Scase et al. 2006; Maglennon et al. 2008; Berlato et al. 2015; Smith et al. 2017).

The KIT protein is a tyrosine kinase receptor that is a product of the c‐KIT proto‐oncogene. Mutations in c‐KIT result in aberrant cytoplasmic expression of KIT in 9–30% of canine MCTs, with high‐grade tumors more likely to have a mutation. Immunohistochemistry protocols for the detection of the KIT receptor expression are well established. Increased expression of KIT in the cytoplasm of neoplastic mast cells is a strong indicator of increased risk of local tumor recurrence and a decreased survival time (Kiupel et al. 2004).

Histologic panels that employ multiple markers are now available at various veterinary pathology laboratories to facilitate prognostication, especially for grade II MCTs.