H. Sasano et al., DETECTION OF APOPTOTIC CELLS IN CYTOLOGY SPECIMENS - AN APPLICATION OF TDT-MEDIATED DUTP-BIOTIN NICK END LABELING TO CELL SMEARS, Diagnostic cytopathology, 18(6), 1998, pp. 398-402
We applied TdT-mediated deoxyuridine triphosphate (dUTP)-biotin nick e
nd labeling (TUNEL) to cytologic smears in order to detect the cells u
ndergoing apoptosis. These smears were obtained by scraping the cut su
rface of 9 cases of carcinoma, including renal-cell carcinoma (3 cases
), esophageal squamous-cell carcinoma (3 cases), and gastric adenocarc
inoma (3 cases), and were fixed and prepared by different methods. The
results were also compared with those of tissue sections. TUNEL in sm
ears was generally associated with higher background nuclear stain tha
n in tissue sections. Smears that were fixed in 4% or 8% paraform alde
hyde or absolute methanol exhibited results comparable with those of t
issue sections, with minimum background in all cases examined. There w
ere no significant differences in TUNEL labeling index among tissue se
ctions and smears fixed in 4% or 8% paraformaldehyde or in absolute me
thanol. Smears treated in Carnoy's fixative (3:1 methanol:acetic acid)
and air-dried smears demonstrated a higher background. TUNEL positivi
ty could not be detected in slides decolorized from May-Grunwald-Giems
a stain. Markedly high background which may occur as a result of artif
actural DNA breaks, was also observed in slides decolorized from Papan
icolaou stain, in which TUNEL-positive cells could be evaluated only i
n 3/8 cases. Application of the TUNEL method to cytology specimens has
disadvantages or limitations compared to its application to histologi
cal sections, bur the method is considered the most suitable one for d
etecting cells undergoing apoptosis in cytology materials. (C) 1998 Wi
ley-Liss, Inc.