This test is used to assess Tumor cell proliferation and also assess prognosis in patients with Bladder, Kidney, Lung, Ovary, Prostate or Thyroid malignancy. It also assists in grading neuroendocrine tumors. This test is used to assess the proliferation of tumor cells in all types of Cancer. Ki-67 is a nuclear non- histone protein present in low levels in Quiescent cells and it increases in proliferating cells. This is the reason why Ki-67 is termed as a specific nuclear marker for cell proliferation by using IHC (Immunohistochemical)Method.