Tumor regression after intralesional injection of mycobacterial components emulsified in 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene (squalene), 2,6,10,15,19,23-hexamethyltetracosane (squalane), peanut oil, or mineral oil.

The influence of mineral oil, squalane, squalene, or peanut oil on the antitumor activity of emulsified Bacillus Calmette-Guérin cell walls or emulsified trehalose-6,6'-dimycolate was studied in mice, each with an established transplant of a syngeneic fibrosarcoma. Each animal received an intratumoral injection of Bacillus Calmette-Guérin cell walls (0.6 mg/mouse) or trehalose-6,6'-dimycolate (0.1 mg/mouse) emulsified in 1 to 10% oil. Emulsions of squalene or squalane but not peanut oil were effective substitutes for mineral oil as carriers of Bacillus Calmette-Guérin cell walls in the treatment of the tumor. Trehalose-6,6'-dimycolate was therapeutically active when it was incorporated in any of these four oils. The number of animals in which tumor regressed completely depended on the concentration of oil in the emulsion.