Regarding effector B cells-derived antibodies (often IgG) [371]; they have demonstrated anti-tumour activity in serum from patients with cancer, as reported in medullary breast cancer (antibodies directed against aberrantly exposed β-actin in apoptotic tumour cells) [376]; lung cancer (anti-p53 antibodies) [376] and ovarian, pancreatic, gastric, breast and lung cancer (antibodies against MUC1, present in serum from patients with cancer at early stages) [371] (Table 2). Here, ACTB is linked to lung cancer.