Can pressure sores cause cancer?

Pressure sores: A small percentage of chronic ulcers can become cancerous, but this is unusual and especially so for pressure ulcerations. Any wound that has been present for a long time that has not responded to usual forms of treatment by trained wound professionals can be considered for biopsy to be read by a trained pathologist.

Yes but rare: They are more likely to have dead tissue or get infected but can rarely develop skin cancer.

Rarely: Cancer can grow in long standing pressure wounds. These cancers are rare. They are named marjolin's ulcers after a french man.