Antibodies are provided which bind human and Macaca fascicularis CEACAM5 proteins, as well as isolated nucleic acids, vectors and host cells comprising a sequence encoding the antibodies. Also provided are immunoconjugates comprising the antibodies conjugated or linked to a growth-inhibitory agent, and to pharmaceutical compositions comprising the antibodies, or immunoconjugates. The antibodies or immunoconjugates are used for the treatment of cancer or for diagnostic purposes.

Provided herein are methods, assays and kits for detecting methylated genomic DNA and one or more protein biomarkers in one or more biological samples. In some aspects, the disclosure provides methods, assays and kits for detecting or prognosing a proliferative disease, such as colorectal cancer, in a subject based on the presence of methylated genomic DNA and one or more protein biomarkers in one or more biological samples.