Fig. 3.

LOH in B2M is found in resistance and non-responding patients treated with CPB. a Illustration of the deletion locations on chromosome 15 overlapping the B2M locus found in Pat99 (blue line); and the total copy ratios of target regions on chromosome 15 in each biopsy. Red dashed lines indicate an absolute total copy number of 2 as inferred by ABSOLUTE. A deleted region overlapping the B2M locus is seen in all samples. Top row indicates the timeline of treatment (blue–regression, orange–progression). b–d Samples from Pat99 (b), Pat25 (c), and Pat272 (d) were stained with an antibody cocktail for melanoma cells (mel.cocktail) using anti-melanosome (HMB45), anti-MART-1/melan A and anti-Tyrosinase, to discern melanoma cells from normal cells; or with an antibody specific for B2M. Colored boxes indicate B2M expression scores: B2M scoring was estimated by using four different levels of expression in the tumor fraction: minimal, 0–10%; low, 10–50%; intermediate, 50–80%; and high, 80–100%, B2M expression in the tumor fraction. Original magnification ×100