Trisomy 12 positive CLL cells, or “+12 CLL” cells, often present unique characteristics, such as atypical morphology (e.g., unusual cleaved or lympho-plasmacytoid appearance under a microscope), increased proliferation rate, a higher expression of CD38, unmutated immunoglobulin heavy chain variable region (IGHV) genes, positive zeta chain-associated protein kinase 70 (ZAP70) expression, Notch Receptor 1 (NOTCH1) gene mutation, a high risk of Richter transformation, and so on [5]. The gene discussed is NOTCH1; the disease is B-cell chronic lymphocytic leukemia.