If someone had cancer all over would bloodwork show abnormalities?

Yes it very likely w: Advanced cancer will often not show in the blood but its effects do show in the blood tests. But these effects ar eoften non specific like in the form of anemia, high platelet count, high sedimentation rate and often effects on the liver functions such as low Albumin level, high alkaline phosphatase and high ldh levels. These are all indirect clues, basiacally showing unhealthy bodily functions.

Depends on the type: Certainly, leukemias or lymphomas which are cancers that affect the blood elements can show up as abnormalities in the white blood cell count and profile on routine blood tests. Other cancers may show their effect indirectly. For example, diffuse cancer can lead to anemia. Other blood tests such as liver function tests can be abnormal if there is tumor infiltrating the liver.