The disclosure provides agents that inhibit granulin signalling for use as medicaments to reduce cancer stem cell activity in the treatment of cancer. The disclosure also provides agents that inhibit soluble granulin signalling for use in the treatment of cancer. The treatments of the disclosure may be of particular utility in breast cancer prostate cancer and melanoma, and are also of use in treatment of cancers associated with hypoxic tumours. Suitable agents may include those that inhibit granulin expression, inhibit granulin cleavage, or bind to and inhibit soluble granulin. Such agents may be used in combination with inhibitors of angiogenesis.
