Simultaneous stimulation of growth of malignant tumors with epithelioid and sarcomatous nature in experiment.

Abstract

e23517 Background: The relevance of studying multiple primary malignant tumors (MPMTs) is determined by poor understanding of their pathogenesis. Our purpose was to create an experimental model of synchronous MPMTs with the stimulation of malignant growth of tumors with different histostructure. Methods: The study included 20 male BALB/c Nude mice. The main group included mice with simultaneous subcutaneous inoculation of tumors: murine B16/F10 melanoma (0.5 ml of suspension diluted 1:20 in saline solution) below the left scapula and rat sarcoma 45 (0.5 million tumor cells in 0.5 ml of saline solution) below the right scapula. Control groups included males with melanoma or sarcoma inoculated at the same dosage and volume as in the main group. Results: In the model of synchronous MPMTs, tumors appeared faster than in controls: melanoma–by 3 times, sarcoma–by 2 times; their volume was larger: melanoma–by 2.2 times, sarcoma–by 3.2 times. Melanoma metastasized, in addition to typical sites (the lungs, spleen, liver), into sarcoma 45 to the side adjacent to the chest, under the tumor node. The survival of mice with MPMTs was lower. The morphological structure of melanoma metastasis into sarcoma 45 was represented by large lamellar-rounded epithelium-like cells of melanosarcoma type with transparent cytoplasm and nuclei with a high frequency of pathological mitosis figures. Bundles of elongated spindle-shaped melanocytes with processes of the cytoplasm were determined in some melanoma areas, as well as alveolar and concentric structures. Conclusions: Synchronous subcutaneous inoculation of murine B16/F10 melanoma and rat sarcoma 45 to male BALB/c Nude mice increases their malignant potential due to an exchange of “structural information"; as a result, sarcoma acquires impulses of proliferative activity of melanoma, which, in turn, adapts and “mimics” a tumor into which it is going to metastasize.