Ki67 Immunoreactivity Is Retained in Acetone-fixed Cryostat Sections Stored at - 20°C

Abstract

The authors studied the retention/loss of immunoreactivity in frozen tissue over a period of 8 weeks using a variety of storage strategies. Ki67 immunoreactivity is com monly used to assess the growth fraction of tumors in frozen histopathology sections. Many antigens are lost with prolonged storage, even in frozen specimens. To evaluate the loss of Ki67 in frozen tissue, 30 tumors were studied over a storage period of 8 weeks. Cryostat sections, acetone-fixed and stored at — 20°C for 8 weeks, showed identical immunoreactivity to tissue stained immediately on arrival in the laboratory. The other methods gave less satisfactory results. The authors conclude that routine acetone-fixed frozen sections provide excellent results for up to 8 weeks when stored at - 20°C. Int J Surg Pathol 1(2):135-138, 1993