Analysis of ADVIA Myeloperoxidase Cytogram LUC Angle Does Not Distinguish Acute Myeloid Leukemia From Acute Lymphoblastic Leukemia or Lymphoblastic Lymphoma in Dogs.

BACKGROUND

Acute myeloid leukemia (AML) is difficult to distinguish from lymphoblastic leukemia or lymphoma (LL) on morphologic features alone. Therapeutic approaches for AML versus LL differ, and immediate therapy is often needed due to patient illness and rapid disease progression. Immunophenotyping is required for the distinction of AML from LL but is often not rapidly available. Hence, a routinely available method for distinguishing AML from LL at the time of diagnosis, such as myeloperoxidase (MPX) activity in tumor cells, is desirable.

OBJECTIVES

To determine whether MPX activity on the ADVIA peroxidase cytogram differentiates AML vs LL, as judged by a lower angle of a line intersecting the large unstained cell (LUC) cluster and the x-axis on the ADVIA 2120 MPX cytogram (MPX LUC angle).

METHODS

Dogs with suspect acute leukemia were prospectively enrolled, and ADVIA-based hematology, flow cytometry, and cytochemical staining were performed in a multi-institutional study. An observer blinded to sample identity determined the MPX LUC angle with Fiji software.

RESULTS

Forty-four cases met the inclusion criteria and were grouped as AML (n = 30) or LL (n = 14). No significant difference in the mean MPX LUC angle was identified between AML and LL (p = 0.9). MPX cytochemical staining did not correlate with MPX LUC angle (Rsp = 0.004, p > 0.9).

CONCLUSIONS

The angle of the LUC population on the ADVIA MPX cytogram cannot be used as a rapid test to differentiate AML from LL.