Because of the cancer or because of the depression. Some cancers are hereditary. But that doesn't mean ur daughter will get it. Cancer can be caused by life style. Depression can also be hereditary but I do think some are caused by imbalances, like thyroid, potassium, etc and once that is corrected no depression.
Whatever the Dad's disorder is, you can do an internet search to find out if it is inheritable. Please keep in mind that even if a disorder is inheritable, it may not mean there's a 100% chance of passing it on. For example, some dementias can be inherited, but that specific gene still needs to actually be passed on to the child.
I'm not sure how you found your way to the agingcare forum, no one here is able to answer that because we are all just caregivers who give each other advice about the challenges of caregiving. I'd suggest you search the whole web with you questions, and include as many specifics about whatever condition (cancer? depression?) you are dealing with.
You need to tell us what disorder.