This book comprises scientific information regarding the identification of the p53 isoform protein in malignant hematologic diseases, which impacts the clinical management of ill patients. In recent years, more attention has been paid to the importance of the p53 protein in terms of chronic lymphocytes leukemia, (CLL) in progression to Richter Syndrome, which is characterised by low survival of patients and non-response to classical conventional chemotherapy, due to mutations in the p53 gene.The book deals with theoretical concerns, but also with practical considerations, highlighting the great need for updated research in the biological sciences in general, and in medicine in particular.