These nanosized polymeric CA-4 prodrugs applied at a dose of 50 mg/kg b.w. (injections were carried out on days 1, 5 and 9 via tail vein after tumours formed in by C26 in Balb/mice reached approximately 100 mm3) significantly prolonged retention of such a conjugate in plasma and tumour tissue, and anticancer therapy itself was conducted mainly around the tumour vessels due to low tissue penetration in solid tumours [143]. The gene discussed is CA4; the disease is neoplasm.