The Annals of Thoracic Surgery, Vol 38, 627-632, Copyright © 1984 by The Society of Thoracic Surgeons
A family of epidermoid lung cancer models
JR Benfield, WG Hammond, EC Shors, R Paladugu, HY Pak and RL Teplitz
A method of sustained release implantation has been developed whereby
Silastic cylinders, impregnated with benzo[alpha]pyrene (BP) or
methylcholanthrene (MCA) each at 2% (low dose) and 10% (high dose)
concentrations, were inserted into the bronchus intermedius of hamsters.
High-dose BP and MCA, and low-dose MCA had first-order exponential release
rates: the half-time of release was 40 days for high-dose BP, 30 days for
high-dose MCA, and 165 days for low-dose MCA. Release rate of low-dose BP
was a second-order function: half-time of release was 40 days. Atypical
squamous metaplasia was noted by 4 weeks in more than 65% of hamsters after
insertion of each high-dose carcinogen but in less than 30% with the
low-dose carcinogens. Carcinoma in situ was noted approximately 8 weeks
after high-dose BP and 19 weeks after low-dose BP. At about 15 to 17 weeks
after a high- dose carcinogen, 64% of animals had invasive epidermoid
cancer, whereas after a low-dose carcinogen, only 21% did. After 25 weeks
of exposure to a high-dose carcinogen, more than 85% of hamsters had
invasive epidermoid cancer; up to 52 weeks were required for invasive
epidermoid cancer to develop in 30% after a low-dose carcinogen. Measured
by image analysis, nuclear deoxyribonucleic acid content of cells with
severe atypical squamous metaplasia was greater than tetraploid (mean +/-
standard deviation [SD], 3.77 +/- 1.4), whereas cells with invasive
epidermoid cancer were suprahexaploid (mean +/- SD, 6.48 +/- 3.6). These
differences are significant (p less than 0.05).(ABSTRACT TRUNCATED AT 250
WORDS)
