Desmoglein-3 Is Inferior to Cytokeratin 5 and p63 in the Cytologic Diagnosis of Squamous Cell Carcinoma (SQC) of the Lung.
Scott R Lauer, Momin T Siddiqui, Cynthia Cohen, Michelle D Reid. Emory University Hospital, Atlanta, GA
Background: Current treatment strategies for lung carcinoma are dependent on the accurate histologic and cytologic classification of these tumors. Several immunohistochemical (IHC) stains have emerged as frontrunners in their diagnosis and subtyping. One such IHC stain is desmoglein-3 (DSG-3), a calcium-binding transmembrane glycoprotein component of desmosomes in vertebrate epithelial cells. It has recently been shown to have a high sensitivity and specificity for the diagnosis (Dx) of lung SQC. We examined DSG-3 in 43 histologically proven lung carcinomas and compared its performance to that of cytokeratin 5 (CK5) and p63, well-known markers of SQC.
Design: A total of 43 resected/biopsied histologically confirmed lung adenocarcinomas (AD) (25), SQC (13) and poorly differentiated carcinomas (PDC) (5) with previous FNA and adequate cell blocks were selected for IHC staining with SQC markers DSG-3, CK5 and p63. Staining was graded as (0), negative; focal, <30% of cells with cytoplasmic staining; and diffuse, ≥ 30% of cells staining. Based on IHC findings a cytologic Dx was rendered and compared to the gold standard histologic Dx.
Results: The results are summarized in Table 1.
|Stain||DSG-3||CK5||p63||CK5 & p63|
|AD (n=25)||1 (4%)||4 (16%)||6 (24%)||0 (0%)|
|SQC (n=13)||6 (46%)||12 (92%)||10 (77%)||10 (77%)|
|PDC (n=5)||1 (20%)||1 (20%)||1 (20%)||1 (20%)|
|Total (n=43)||8 (19%)||7 (16%)||17 (33%)||11 (26%)|