Cell surface NIS protein levels are more variable than corresponding NIS mRNA levels detected by oligonucleotide microarray. A human breast tumor TMA composed of 28 breast tumors with corresponding cDNA microarray data was immunostained with the p442 anti-hNIS antibody and each tumor was evaluated according to the level of cell surface NIS protein on a scale of 0, 0/1+, 1+, 1+/2+, 2+ and 3+. NIS mRNA levels detected by the 211123_at NIS probe set of the HG U133 Plus 2.0 Affymetrix microarray platform were examined and compared among breast tumors expressing each assigned level of cell surface NIS protein. Maximum, minimum and median NIS mRNA levels for each level of cell surface NIS are indicated. As shown by the box and whisker plot, there was no correlation between NIS mRNA and cell surface NIS protein among breast tumors. The length of the box represents the interquartile range (i.e., the middle 50% of the data). The median (line through the middle of each box), the lower quartile (bottom line of each box), and the upper quartile (top line of each box) are also specified on the plot for each level of cell surface NIS protein. The sample minimum and maximum values are represented as T-shaped lines extending from the ends of the box. Maximum outliers (gray squares) and minimum outliers (black diamonds) are also plotted. Representative images of breast tumors scored as 0 (18%, n = 5), 0/1+ (21%, n = 6), 1+ (25%, n = 7), 1+/2+ (18%, n = 5), 2+ (11%, n = 3) and 3+ (7%, n = 2) for cell surface NIS protein (denoted by arrows) are also shown (400×).