Doubled chromosome. Coloured scanning electron micrograph (SEM) of a diplochromosome after treatment with etoposide. Chromosomes normally consist of two identical chromatids joined at a centromere, diplochromosomes have four chromatids. Etoposide is a drug that is used to treat some types of cancer, mainly testicular and small-cell lung cancer. It prevents malignant (cancerous) cells from spreading by interfering with cell division mechanisms, eventually causing cell death. Diplochromosomes are a result of etoposide interference, as chromatids are not separated after replication as they normally would be. Etoposide also physically damages chromosomes. Magnification: x16,800 when printed 10cm wide.