A small proline-rich protein, spr1: specific marker for squamous lung carcinoma.
We have identified a small proline-rich protein, spr1, which is a sensitive and specific marker for distinguishing squamous cancer from the other cell types of lung carcinoma. A rabbit antiserum against a 15-amino-acid peptide of the C-terminus of spr1 was prepared. The specificity of this antiserum was demonstrated in normal squamous tissues by Western blotting and immunohistochemical analysis. Expression of spr1 in 63 cases of formalin-fixed and paraffin-embedded human bronchogenic carcinoma was studied by immunohistochemical staining. For these 63 cases of bronchogenic carcinoma previously diagnosed by hematoxylin/eosin (H/E) staining, the number of spr1-positive cases/total number of H/E cases of each cell type of lung cancer were as follows: 20/20 of squamous carcinoma, 2/18 of adenocarcinoma, 4/14 of large-cell carcinoma, and 0/11 of small-cell lung carcinoma. Squamous differentiation evidenced by spr1 expression was substantiated by the presence of squamous features observed under transmission electron microscopy (TEM). We conclude that spr1 is a sensitive and specific marker for squamous bronchogenic carcinoma.
University of California, Davis Cancer Center, Division of Hematology/Oncology, Sacramento 95817, USA.
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D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000648:ultrastructure; D055233:Cornified Envelope Proline-Rich Proteins; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D008565:Membrane Proteins; D008854:Microscopy, Electron; D014176:Protein Biosynthesis; D011506:Proteins; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D055233:Cornified Envelope Proline-Rich Proteins; D008565:Membrane Proteins; D011506:Proteins