FCM data analysis on heterogeneous specimens

Abstract

Most clinical specimens, whether normal/reactive or harboring neoplastic cells, are heterogeneous. The highest degree of heterogeneity is seen in bone marrow samples. Solid lymphoid tissues such as tonsils and lymph nodes are less heterogeneous because the granulocyte/monocyte component is usually insignificant. The benign nonpurulent effusion, when not overloaded with a large number of macrophages or mesothelial cells, is the least complicated type of specimen consisting of B- and T-cells in a similar proportion to that seen in the blood. The FCM graphics in heterogeneous samples are inherently complex, displaying multiple clusters, some of which may be overlapping. The task in analyzing these dot plots is twofold: first, to determine whether the sample is benign/reactive or contains a neoplastic population (which may or may not be evident at first glance) and, second, to characterize the tumor cells, if present. In some malignant conditions such as a myelodysplastic syndrome (MDS), CML, or CMMoL, an overt neoplastic cluster (i.e., increased blasts) may not be present. The FCM graphics often demonstrate several features useful for recognizing these disorders however, such as an altered proportion of the granulocytic or monocytic component and qualitative antigenic abnormalities in the myeloid (e.g., altered maturation curves), monocytic, or erythroid elements.