Gene Markers as Predictors of Nodal Metastasis and Outcome

Abstract

Objective: 1) Investigate the correlation between percentage of metastatic tumor in lymph nodes from patients with squamous cell carcinoma (SCC) of the head and neck and level of expression of 3 marker genes: pemphigus vulgaris antigen (PVA), parathyroid hormone related peptide (PTHrP), and tumor-associated calcium signal transducer (TACSTD1). 2.) Understand the relation of these markers and clinical outcomes. Method: Four hundred forty-eight grossly negative lymph nodes from 92 patients with SCC were evaluated for expression of the gene markers PVA, PTHrP, and TACSTD1 using real-time PCR. Confirmation of metastasis was determined by histological examination. The expression of these markers was analyzed versus tumor percentage using correlation and linear regression. Results: All 3 markers were studied independently and were statistically significant predictors of tumor percentage in the lymph nodes at a significance level of 0.05. PVA had the strongest correlation with tumor percent with a correlation coefficient of 0.68, an r squared of 0.46, and a P value <.001. PTHrP had a correlation coefficient of 0.39, r squared of 0.16, and a P value of .003. TACSTD1 had a correlation coefficient of 0.38, r squared of 0.15, and a P value of .004. Conclusion: All 3 markers are statistically significant predictors of percent tumor in grossly negative lymph nodes. PVA had the strongest correlation. Further analysis will include a multivariate regression to account for possible confounding. Since expression correlates with tumor percent, we expect that expression levels will also correlate with clinical outcomes.