Choriocarcinoma: Growth Patterns in Hamster Tissues

CHORIOCARCINOMA is a highly invasive tumour that retains some of the peculiar properties of normal immature human trophoblast 1 . In order to study the manner in which it invades tissues, we inoculated small fragments of transplantable human choriocarcinoma into the following sites in 19 young (70–90 g) female Syrian hamsters (Dennen): uterine broad ligament, peritoneal cavity, lung, liver, brain, thigh muscle, vena cava, hepatic portal vein, and internal jugular vein. Testicular inoculation was carried out in one male hamster. The tumour used was the Greene choriocarcinoma (kindly supplied by Dr. Roy Hertz), originally isolated in 1960 by Roy Hertz, carried by serial passage in the hamster cheek pouch, and similar in behaviour to the WO strain described by Hertz 2 . Although cortisone is not needed to maintain growth of the Greene choriocarcinoma in the cheek pouch, we gave it to 15 of the 19 hamsters in this preliminary work with the hope of ensuring tumour growth at the various inoculated sites 3 . For direct implantation into organs, two–ten 3-mm tumour fragments were inoculated into each site by cannula (Lundy–Irving caudal needle). For intravenous inoculation, the tumour was minced with Bard Parker knives into fragments less than 1 mm in diameter. About 50 of these tiny fragments were suspended in 0.1 ml. or less of Gey's balanced salt solution, and slowly injected with a tuberculin syringe through a 21-gauge hypodermic needle. All hamsters were autopsied within 7–16 days.