ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the diagnostic significance of sublingual nodules for metastasis of patients with breast cancer and further to explore the mechanisms of sublingual nodules.</p><p><b>METHODS</b>The image data of 117 in-patients with breast cancer in stage I-IV in Tianjin Medical University Cancer Institute and Hospital from December 2009 to September 2011 were assessed retrospectively. All photos of patients' tongue were recorded by the digital camera of uniform type within 1 month after serological examination and regular re-examined by computed tomography (CT), magnetic resonance imaging and positron emission tomography CT. The presence of sublingual nodules was the positive standard. Chi square test and two-independent-sample test were used to determine the diagnostic value between the status of sublingual nodules and Clinico-pathological characteristics. The optimal cut-off of uric acid (UA) level to diagnose sublingual nodules was determined by receiver operating curve (ROC) analysis.</p><p><b>RESULTS</b>Breast cancer patients with sublingual nodules had a higher risk of recurrence and/or metastasis than patients without it (P<0.001). Sublingual nodules was significantly correlated with increased serum UA level (P=0.001). The optimal cut-off value of UA level to diagnose sublingual nodules was 290 μmol/L. Furthermore, the elevated serum UA level (≥290 μmol/L) was significantly related to breast cancer recurrence and/or metastasis (P<0.001).</p><p><b>CONCLUSIONS</b>Sublingual nodules were potential diagnostic markers for metastatic breast cancer. The formation of sublingual nodules was associated with elevated level of serum UA.</p>