A study in Saudi Arabia reported that the CD66c, CD34 and CD10 positivity phenotype were associated with, but not perfectly predictive of, the t(9;22) translocation, which is common in B-ALL, particularly among adults.8 Of note, CD66c positivity in B-ALL is also common in cases with hyperdiploidy.24,25 Among adults, it has a worse prognosis,26 but outcomes may be enhanced with the inclusion of tyrosine kinase inhibitors specific for the fusion gene BCR-ABL. The gene discussed is CD34; the disease is acute lymphoblastic leukemia.