Correlation of Beta-2 Adrenergic Receptor Expression in Tumor-Free Surgical Margin and at the Invasive Front of Oral Squamous Cell Carcinoma

Abstract

Background. The beta-2 adrenergic receptor is expressed by neoplastic cells and is correlated with a wide spectrum of tumor cell mechanisms including proliferation, apoptosis, angiogenesis, migration, and metastasis. Objectives. The present study aimed to analyze the expression of the beta-2 adrenergic receptor (β2-AR) in tumor-free surgical margins of oral squamous cell carcinomas (OSCC) and at the invasive front. Sixty-two patients diagnosed with OSCC, confirmed by biopsy, were selected for the study. The clinicopathological data and clinical follow-up were obtained from medical records and their association with β2-AR expression was verified by the chi-square test or Fischer's exact test. To verify the correlation of β2-AR expression in tumor-free surgical margins and at the invasive front of OSCCs, Pearson's correlation coefficient test was applied. Results. The expression of β2-AR presented a statistically significant correlation between the tumor-free surgical margins and the invasive front of OSCC (r = 0.383; p = 0.002). The immunohistochemical distribution of β2-AR at the invasive front of OSCC was also statistically significant associated with alcohol (p = 0.038), simultaneous alcohol and tobacco consumption (p = 0.010), and T stage (p = 0.014). Conclusions. The correlation of β2-AR expression in OSCC and tumor-free surgical margins suggests a role of this receptor in tumor progression and its expression in normal oral epithelium seems to be constitutive.

Figure 1

Correlation of the averages of β2-AR immunoexpression in OSCC specimens. The lines correspond to the cut-off point that classifies the invasive tumor fronts (green line) and the surgical margins (blue line) as exhibiting weak/negative (averages 0.62 to 23.86) or moderate/strong (averages 25.99 to 79.63) β2-AR expression.

Figure 2

Expression pattern of β2-AR in OSCC specimens. (a and b) OSCC with strong expression of β2-AR in both surgical margin and invasive front of tumor. (c and d) OSCC with weak expression of β2-AR in both surgical margin and invasive front of tumor. (e and f) OSCC with reduced expression of β2-AR at the invasive front of the tumor when compared to surgical margin. Note the membranous and/or cytoplasmic expression pattern of β2-AR in immunostained cells (a, b, c, d, e, and f: immunohistochemistry β2-AR, original magnification ×400).