While P-gp poses a significant challenge, it is important to note that not all therapies are affected; for instance, monoclonal antibodies targeting cell surface markers such as CD20 (used in lymphomas) or CD38 (used in multiple myeloma) are not P-gp substrates and, thus, their efficacy is not directly compromised by P-gp overexpression. This evidence concerns the gene PGP and AL amyloidosis.