Study Tumor Biology Research Articles

Hyperplastic and Inflammatory Nodules in the Canine Mammary Gland<xref ref-type="fn" rid="FN1">2</xref>

An attempt was made to recognize by subgross morphology with dissecting microscope magnifications any abnormalities in the canine mammary glands and then to classify these structures by histopathologic criteria. Techniques developed for demonstrating hyperplastic lesions in mammary glands of rodents were applied to whole mammary glands of untreated female beagle dogs. 8 intact purebred female beagle dogs were obtained from the Radiation Biology Laboratory at the University of California in Davis where they had been maintained since birth. Any unusual structural change as compared to the normal lobularity of the mammary gland was considered an atypical nodule. Such nodules were classified histologically as normal inflammatory or proliferative. There were 763 atypical nodules studied histologically. Evaluation of the mammary gland of the dog by the techniques described could shorten considerably the time required and improve the accuracy of oncologic and drug evaluation studies. Recognition of preneoplastic changes in the canine mammary gland could have useful applications in the study of tumor biology and might have significant relationships to the current study of the human mammary gland. This might include development of a more reliable and consistent diagnostic technique for early mammary tumors.

Tumors of the skin. XII. Topical 5-Fluorouracil for epidermal neoplasms.

AbstractOur studies have been carried out in over 500 patients with an aggregate of more than 15,000 lesions for observation periods in excess of 5 years. Topical chemotherapy with 5‐FU was shown to result in selective eradication of premalignant and superficial malignant lesions of the skin. Since the action of 5‐FU is selective, it produces minimal or no effects on normal tissues adjacent to tumors. Healing therefore occurs with slight or no apparent scarring. Topical chemotherapy is indicated for solar keratoses and other precancerous lesions as well as for multiple superficial primary skin cancers when standard therapeutic measures are not suitable because large areas of the skin are involved by persistently developing tumors. Topical cancer chemotherapy induces the resolution of premalignant skin lesions and prevents their further development to the malignant stage. Early primary skin cancers and premalignant lesions react to topical antitumor agents before they are otherwise clinically detectable. These tumors can therefore be eradicated before they present significant clinical problems. Early detection and eradication of skin cancers and premalignant skin lesions furthermore result in the reduction of the subsequent incidence of clinically significant tumors. Local chemotherapy therefore appears to have prophylactic value. Local administration of 5‐FU results in high concentrations of the antitumor agent at the tumor site, although the total amount administered and the rate of absorption are relatively low. General toxicity such as bone marrow depression and other systemic side‐effects are therefore not encountered with local cancer chemotherapy. Superficially located neoplasms are suitable model systems for the study of tumor biology. Local chemotherapy indicates that differential and selective chemical effects can be produced in neoplastic cells and their normal counterparts. Studies on local chemotherapy demonstrate that the selective eradication of malignant disease in many by chemical means is feasible.

Growth-rate analysis of experimental tumors. A systematic method.

A uniform and rational analysis of growth rates of experimental tumors would greatly facilitate interpretation and comparison of many studies of basic tumor biology. Comparative analysis of spontaneous human tumors tends to be handicapped by wide variation in growth rates. However, animal tumors, and especially transplanted tumors, lend themselves well to group analysis. Widely varying methods of recording are apparent in published studies of tumor biology and of effects of various experimental treatments. Some of the criteria which have been used in assessing growth rates are: (1) volume of tumors, derived from external measurements; (2) weight or volume of excised tumors; (3) volume of ascites cells, centrifuged; (4) tumor diameter, or mean diameter; (5) tracings of cross sectional areas of tumors; (6) calculated doubling time during the interval of observation; (7) calculated number of volume doublings in X time; (8) coefficient of volume expansion per unit time; (9) time required