One possible option for detecting cancer cells is so-called DNA cytometry, which measures the amount of nuclear DNA to detect deviations from normal DNA content and to determine UVLED absorption within the boundaries of the nucleus. In one exemplary embodiment, the position and / or size of the nucleus may be (roughly) determined in the at least one cell by using UV light and / or phase contrast microscopy. If UV light is used, UV light with wavelengths between about 240 nm and about 280 nm should be preferred. It is particularly preferred that the wavelength is, for example, about 250 nm, 255 nm or 260 nm.