Immunohistochemical Scoring of Lung Tumor Tissues

Fresh lung tumor tissues were obtained from patients who were undergoing surgical resection of the primary tumor. All human tissue samples were obtained and analyzed in accordance with procedures approved by the institutional review board of the University of California, San Francisco (IRB H8714–22 942–01). The tissue microarray sections were immunostained as previously described [55 (link)]. The following scoring system was used: −, no stain; +, weak staining (10% or above stained cellularity considered as positive); ++, moderate staining (30% or above stained cellularity considered as positive); +++, strong staining (50% or above stained cellularity considered as positive). All scoring was done under low power objective lens (20 ×) with a Zeiss Axioscop 2 microscope (Carl Zeiss Inc, Germany). Images were taken under 20 × or 40 × objective lens.