The U-2 OS cell line was derived from a human osteosarcoma, but the disease is not solely experienced by Homo sapiens. A wide array of other mammals may also develop this type of cancer. Generally of most concern in this regard is the occurrence of bone tumors in pets, such as cats and dogs. Dogs suffer from the disease much more commonly than feline species, and large or giant breeds are especially prone to osteosarcoma due to the greater amount of growth their bones must undergo. Similar to humans, tumors most frequently develop in the largest bones, such as those of the legs. Unlike people, however, in most dogs, osteosarcoma is more common in middle aged or older individuals. Yet, in larger animals, the disease is more likely to develop earlier in life.

The human bone cancer (U-2 OS) cell culture featured in the digital image above was labeled for mitochondria and the cytoskeletal F-actin network with MitoTracker Red CMXRos and Alexa Fluor 488 conjugated to phalloidin, respectively. Nuclei were counterstained with the ultraviolet-absorbing probe DAPI. Images were recorded in grayscale with a QImaging Retiga Fast-EXi camera system coupled to an Olympus BX-51 microscope equipped with bandpass emission fluorescence filter optical blocks provided by Omega Optical. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.