Based on these findings, the authors decided to split the population of the present study into two groups (with or without lymph nodes metastasis), and to investigate the prognostic role of different clinical (hypercalcemia and tumor size) and histologic factors besides Ki67 (MC, tumor pattern, presence of tumor necrosis, lymphatic and vascular tumor invasion, inflammatory infiltration, anisocytosis and anisokaryosis) (see Table 4) in the group with the worst prognosis (dogs with regional metastatic lymph-nodes). Here, MKI67 is linked to vascular neoplasm.