Cell cultures can be easily overgrown by fungi, especially yeast. This is because some fungi can grow very well in cell culture media, as the media contains everything an opportunistic fungus needs.
I suggest that fungal media requires, saccharides, Nacl, bactotryptone or all culture yeast extract, but by doing sone modification for human fungi you can grow both cancer cells as well as fungi.Therefore, media supplemented eith with FBS or FCS may work for cancer cell culture.