Objective: The goal of this study was to develop a semiquantitative scoring
system for measuring hypoxia in human tumors by an immunohistochemical mar
ker approach.
Methods and Materials: Eighteen patients diagnosed with squamons cell carci
noma of the uterine cervix or head add neck were infused intravenously with
a solution of pimonidazole hydrochloride at a dose of 0.5 gm/m(2). Twenty-
four hours later, four biopsies on average from each tumor were fixed in fo
rmalin, processed into paraffin blocks, and sectioned. Tissue sections were
immunostained for the presence of pimonidazole adducts, Microscopic images
(x200) of immunostaining were captured and quantitated by standard image a
nalysis. images with known amounts of hypoxia spanning ranges of > 0% to 5%
, > 5% to 15%, > 15% to 30%, and >30% were assigned scores of +1, +2, +3, a
nd +4, respectively, Three observers then used this calibrated scoring syst
em to analyze hypoxia in tumor sections in a blinded fashion.
Results: Excellent interobserver reproducibility was obtained with the cali
brated, semiquantitative, immunohistochemical assay for hypoxia in squamous
cell carcinomas.
Conclusion: The calibrated, semiquantitative assay shows promise as an appr
oach to simplifying the quantitation of human tumor hypoxia by immunohistoc
hemical techniques. (C) 2001 Elsevier Science Inc.