Soft tissue sarcoma trial with chlorambucil: This trial is to investigate the effect of chlorambucil, an oral chemotherapy drug, on the immune system of dogs with soft tissue sarcomas. The tumors can be present or incompletely removed by surgery. The study requires blood and lymph node tissue samples to be taken over 3 visits to our hospital over one month. The study covers the cost of the drug and the visits. The owner is responsible for further recommended treatment.