FIXATION REQUIREMENTS FOR THE IMMUNOHISTOCHEMICAL REACTIVITY OF PCNA ANTIBODY PC10 ON CRYOSTAT SECTIONS

In contrast to that in paraffin-embedded tissue, the reactivity of mon oclonal PCNA antibody PC10 on cryostat sections requires a special fix ation procedure as the target epitope is seemingly not accessible to i ts antibody. A panel of Is fixation protocols was investigated. Chille d methanol or acetone, or PLP (paraformaldehyde-lysine-periodate) was found to be unsuitable for skin preparations. A two-step fixation prot ocol was developed for normal skin and basal cell carcinomas. They wer e fixed first in 3.4% buffered formaldehyde, followed by fixation in 2 :1 v/v ethanol-acetic acid. Following this fixation regime, cryostat s ections displayed the same PCNA/PC10 labelling pattern as paraffin sec tions of formalin-fixed tissue.