In the treatment of tumors, microenvironment plays an important role. It often contains immune cells that are so changed that they promote tumor growth. Scientists have introduced a method by which cell samples from tumors and their surroundings can rapidly (under 1 hour) be cycled through staining, destaining, and then restaining with fluorescent antibodies — through attachment of a ”black hole quencher” (fluorescence quencher) by means of ”click chemistry”.