Fig. 1

Semiquantified interpretation system compared with the binary system. a ALK staining patterns zero (no stain, 200´ magnification), b zero ( 400´). c 1+ (uncertain weak stain seen at 200´ magnification), d 1+ (weak cytoplasmic stain seen at 400´ magnification). e 2+ (moderate cytoplasmic stain seen at 200´ magnification), f 2+ (400´). g 3+ (strong cytoplasmic stain seen at 40´ magnification), h 3+ (400´). Scores of 2+ and 3+ are considered ALK positive, while scores of zero and 1+ are considered negative by the binary system