Published in Cancer Detection and Prevention 2001; 25(4):394-405.

Expression Pattern of Hybrid Phenotype in Adult Acute Lymphoblastic Leukemia

Kazunori Nakase, MD, PhD,a,b Kenkichi Kita, MD, PhD,b Hiroshi Miwa, MD, PhD,b Kazuhiro Nishil, MD, PhD,b Hiroshi Shiku, MD, PhD,b Kaori Nasu, MD, PhD,c Hiroo Dohy, MD, PhD,d Tafichi Kyo, MD, PhD,d Nanao Kamada, MD, PhD,e and Hiroshi Tsutani, MD, PhDf

aDepartment of Internal Medicine, Saiseikai Matsusaka Hospital, Matsusaka; bSecond Department of Internal Medicine, Mie University School of Medicine, Tsu; cDepartment of Internal Medicine, Osaka Red Cross Hospital, Osaka; dDepartment of Internal Medicine, Hiroshima Red Cross Hospital, and eDepartment of Hematology, Research Institute for Nuclear and Biology, Hiroshima University, Hiroshima; and fFirst Department of Internal Medicine, Fukui Medical College, Fukui, Japan

Address all correspondence and reprint requests to: Kazunori Nakase, MD, Second Department of Internal Medicine, Mie University School of Medicine, 2-174 Edobashi, Tsu. Mie 514-8507, Japan.

ABSTRACT: We examined the expression of hybrid phenotype in 236 adults with acute lymphoblastic leukemia (ALL; 188 B-lineage ALL and 48 T-lineage ALL). In B-lineage ALL, myeloid antigen (mAg) CDI5 was concentrated in CD1O-CD2O-- cases (49%); CDl3 (42%); and CD33 (43%) in CDIO+CD2O- cases. This trend had no correlation with the presence of Ph1 or t(4; 11) chromosomal abnormality. T-cell antigen CD2, CD4, and CD7 was seen in four, four, and two cases, respectively, and CD4 + and CD7 + cases commonly expressed CDI3 and/or CD33 (CD13/CD33). In T-lineage ALL, expression of mAg, CDI lb (47%), CDI3 (38%), CDI5 (28%), and CD33 (5 1%) was restricted to CD3- cases. B-cell antigen CDI9 was found in two cases with CD7 solely as T-cell antigen, and these cases possessed CDI3/CD33. CD21 was detected in three cases with CD3. In whole ALL, CDI3/CD33 was associated closely with the presence of stem-cell antigen CD34, and in T-lineage ALL, CDI3/CD33 had a significant correlation with additional stem-cell features, such as HLA-DR, multidrug resistance I (MDR I) and c-kit gene expression. Our results suggest that immature ALL cells frequently express B ± M +, T + M +, and occasionally B + T + M ± phenotype; that B + I + M- phenotype is extremely rare; and that mAg expression in B-lineage ALL is complicated as compared to T-lineage ALL.

KEY WORDS: acute lymphoblastic leukemia, c-kit, hybrid phenotype, myeloid antigen, multidrug resistance 1.