CLINICOPATHOLOGICAL ANALYSIS OF MACROPHAGE INFILTRATES IN BREAST-CARCINOMA

We compared macrophage density, assessed by enumeration of peritumoral mononuclear cell immunoreactivity for HAM 56, to clinicopathologic fe atures and to immunostaining for two ''invasion-associated proteases ( Cathepsin D and Urokinase plasminogen activator) in 80 breast carcinom as. Diffuse (2+) infiltrates of HAM 56- positive mononuclear cells wer e present in 27 cases (34%) and 43 (54%) exhibited focal (1+) infiltra tes. Presence of 2+ macrophage infiltrates corre lated significantly w ith poor differentiation. None of the seven well-differentiated cases exhibited 2+ infiltrates, whereas 9/43 (21%) moderately differentiated and 18/30 (60%) poorly differentiated rumors were diffusely infiltrat ed (p=.001). Wide-spread macrophage infiltrates were also more frequen t in cases with advanced stage (23 % of node negative vs 40% of node p ositive cases, p=NS). Forty-four percent of the cases with diffuse mac rophage infiltrates were cathepsin D positive (i.e. in host derived ce lls) vs only 18% with focal macrophage infiltrates (p=.002). A similar relationship was observed between staining for HAM 56 and urokinase-t ype plasminogen activator (p=.02). Disease recurrences (SO months medi an follow-up) were more frequent in patients with 2+ (17/27, 63%) as o pposed to 0+ (1/10, 10%) macrophage infiltrates (p=.01). We conclude t hat the density of stromal macrophage infiltrates is associated with c linical aggressiveness in breast carcinomas. Further, this relationshi p may reflect contribution of host derived macrophages to invasion and metastasis through elaboration of proteases which putatively mediate degradation and remodeling of extracellular matrix.