CCR8 expression in human malignant melanoma. Immunohistochemistry for CCR8 (red) on human melanoma tissue array (A–D), samples of primary melanomas in the skin (E–I), and melanoma metastases in the human lymph node (J–M). Tumors showed various staining patterns for CCR8: membrane (A and B), cytoplasmic (C), or no staining (D). (E–H) Serial sections of human melanoma in the skin immunostained for CCR8 (E and G), or secondary antibody control (F and H). (G and H) Higher magnification of the boxed area in E and F. CCR8, red; endogenous melanin, brown. (I) Highly pigmented melanoma negative for CCR8. (J–L) Metastatic melanoma localized in the subcapsular zone of the lymph node stained for CCR8 (J and L) or secondary antibody control (K) on the serial sections. (L) Higher magnification of the boxed area in J. (M) CCR8 expression in metastatic melanoma localized in the follicular zone of the lymph node. Images are representative of 87 primary tumors and 8 lymph node samples. c, capsule; t, tumor; f, follicle. Bars: (J and K) 200 µm; (A–F, I, L, and M) 100 µm; (G and H) 25 µm.