DNA IMAGE CYTOMETRIC MEASUREMENT AS A SURROGATE END-POINT BIOMARKER IN A PHASE-I TRIAL OF ALPHA-DIFLUOROMETHYLORNITHINE FOR CERVICAL INTRAEPITHELIAL NEOPLASIA
Iv. Boiko et al., DNA IMAGE CYTOMETRIC MEASUREMENT AS A SURROGATE END-POINT BIOMARKER IN A PHASE-I TRIAL OF ALPHA-DIFLUOROMETHYLORNITHINE FOR CERVICAL INTRAEPITHELIAL NEOPLASIA, Cancer epidemiology, biomarkers & prevention, 6(10), 1997, pp. 849-855
Cervical intraepithelial neoplasia grade 3 (GIN 3) is considered a hig
h-risk precursor of invasive cervical cancer. cu-Difluoromethylornithi
ne (DFMO) is a promising antiproliferative chemopreventive agent, The
purpose of this study was to evaluate image cytometric measurement of
nuclear DNA (ICM-DNA) as a surrogate end point biomarker (SEE) in a Ph
ase I trial of DFMO for GIN. Thirty patients with CIN 3 were treated w
ith DFMO at five doses, ranging from 0.0625 to 1.0 g/m(2)/day, for 1 m
onth, Half of the patients had histological responses. Twenty-five pre
-and posttreatment cervical biopsy specimens (from 11 responders and 1
4 nonresponders) were available for this analysis, ICM-DNA was perform
ed on 4-mu m sections cut from formalin-fixed tissue blocks and staine
d with a thionin-SO2 Feulgen reaction, ICM-DNAs for each case were exp
ressed as normalized measurements (against the nuclear modal absorbanc
e of lymphocytes) of the absorbance of each cell of interest and were
presented in bar histograms, The mean normalized summed absorbance (Si
gma ODn) was obtained as a mean histogram of the cell population of in
terest, Nineteen (76%) of 25 patients had a significant decrease in Si
gma ODn after DFMO treatment, Posttreatment values were significantly
lower than pretreatment values in a paired analysis, and responders ha
d significantly lower values than nonresponders, Analyses of different
ICM-DNA references, including percentile values of Sigma ODn distribu
tion, DNA malignancy grade, and 5c exceeding rate, showed a decrease o
f mean Sigma ODn during DFMO treatment, In addition, the summed posttr
eatment Sigma ODn histograms also showed progressively shorter right s
houlders compared with pretreatment histograms in both responders and
nonresponders, We concluded that the modulation of Sigma ODn reflected
the chemoprevention effect of DFMO even before morphological changes
appeared, and thus, ICM-DNA may be useful as a SEE in chemoprevention
trials of DFMO. Additional reasons for using ICM-DNA as a SEE are the
relative simplicity of its use, the high accuracy of the results, the
low cost of the reagents, the ability to use small tissue samples, and
the objectivity and reproducibility of the procedure.