Significance of site-specific prognosis of cancer stem cell marker CD44 in head and neck squamous-cell carcinoma.

In several recent studies, CD44 expression has been associated with aggressive behavior in cancers of different types. CD44 expression is also linked to cancer stem cells, which have been shown to play a significant role in tumor progression and poor prognosis in head and neck squamous cell carcinoma (HNSCC), as well as in other cancers. Although CD44 is a potential prognostic marker, it has not been adopted to wider clinical use as a part of treatment planning in HNSCC patients. The aim of this research was to study whether CD44 overexpression is associated with 5year overall survival in HNSCC. We also studied site-specific associations between increased CD44 expression and 5year overall survival. Associations between relative tumor CD44 expressions and smoking, heavy alcohol consumption, histological grade of cancer, TNM staging and HNSCC staging were also studied. In total, 135 paraffin-embedded blocks from HNSCC patients were stained immunohistochemically with a CD44 antibody and were classified by the anatomic location of the tumor. CD44 overexpression had statistically significant association with decreased 5year survival rates when all HNSCC samples were studied (p<0.001). Significant association between intense CD44 expression and poor 5year survival rates was found in the patients with SCC of the oro- and hypopharynx (p<0.001) and the larynx (p=0.042). In patients suffering from HNSCC in the oral cavity, CD44 overexpression did not have a significant effect on overall 5year survival rates. Heavy smoking of over 10 pack years had a significant association with tumor CD44 overexpression (p=0.009). Only pharyngeal (p=0.046) and laryngeal (p=0.047) SCC, but not oral-cavity SCC, had statistically significant associations between heavy smoking and CD44 overexpression when HNSCC was studied in regional groups. Alcohol consumption and tumor grade did not have a significant association with the tumor's CD44 expression. Our results suggest that CD44 overexpression could be used as a sign of aggressiveness, in addition to the HNSCC staging, as a prognostic factor in pharyngeal and laryngeal HNSCC and to assist in treatment selection.

Pim-1 kinase expression predicts radiation response in squamocellular carcinoma of head and neck and is under the control of epidermal growth factor receptor.

Pim-1 is an oncogenic serine/threonine kinase with poorly defined function in epithelial cancers. In this study, we determined 1) associations of Pim-1 expression with clinicopathological parameters including responsiveness to irradiation in squamocellular cancers of head and neck and 2) how Pim-1 expression is controlled subsequent to irradiation. Moderate to high expression of Pim-1 correlated to poor response to radiation therapy (P = .003). It is also associated to the expression of epidermal growth factor receptor (EGFR, P < .0001), which has been shown to be activated by irradiation. In radioresistant tumors, irradiation promoted nuclear translocation of Pim-1 (P < .005). When directly testing EGFR dependence of Pim-1 expression, up-regulation and nuclear translocation of Pim-1 could be induced through stimulation of EGFR with its ligands EGF or transforming growth factor alpha. Both ligand- and irradiation-induced changes in Pim-1 expression and localization could be inhibited by the monoclonal anti-EGFR antibody cetuximab and by the tyrosine kinase inhibitor gefitinib also targeting EGFR. These results suggest that irradiation-induced activation of EGFR upregulates Pim-1, and Pim-1 may be used as a novel predictive marker of radiation response in patients with squamocellular cancers of head and neck.

Carbohydrates located on the top of the "cap" contribute to the adhesive and enzymatic functions of vascular adhesion protein-1.

Vascular adhesion protein 1 (VAP-1) is an endothelial adhesion molecule with an enzymatic activity. It deaminates biogenic amines, resulting in the formation of aldehydes and hydrogen peroxide. During the enzymatic reaction a transient Schiff base is formed between endothelial VAP-1 and its leukocytic ligand, and this interaction is important for lymphocyte adhesion. VAP-1 monomer has six potential N-linked, and three putative O-linked glycosylation sites and an SSSS sequence potentially forming an attachment site for an adjacent O-linked site. In this work we modeled the carbohydrate decorations on a structural model of VAP-1, and studied which of those potential glycosylation sites are utilized, and whether those decorations accessible to a lymphocyte ligand are important in lymphocyte adhesion and enzymatic activity of VAP-1. We show that, unlike the O-linked attachment sites, all six N-linked glycosylation sites are in use. Furthermore, mutation of the N-linked attachment sites strategically located on the top of the molecule reduces lymphocyte adhesion in non-static conditions, and enhances the catalytic activity of membrane-bound human VAP-1 in static conditions, suggesting that glycosylation regulates the functional properties of VAP-1.

Intratumoral lymphatics are essential for the metastatic spread and prognosis in squamous cell carcinomas of the head and neck region.

Head and neck squamous cell carcinomas (HNSCCs) frequently disseminate to regional lymph nodes. To investigate the possible mechanisms involved, we studied the expression of cancer cell adhesion molecules together with lymphatic vascular and blood vascular markers in a panel of 97 primary HNSCC tumors and correlated expression levels with conventional clinicopathological parameters and with long-term prognosis. In particular, we measured the density of intratumoral and peritumoral lymph vessels as assessed with the marker lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) and the density of tumor CD44, a receptor up-regulated in many metastatic cancers. Intratumoral LYVE-1(+) lymphatic vessels were clearly associated with a higher risk for local relapse as well as with poor disease-specific prognosis (P = 0.02 and 0.0009, respectively). In contrast, a high density of peritumoral LYVE-1(+) vessels was a sign of favorable survival (P = 0.05). Strong primary tumor CD44 expression was associated with a poor prognosis, an increased risk of local recurrence (P = 0.03 and 0.02, respectively), and an increase in resistance to radiation therapy (P = 0.03). CD44 was the only factor with an independent prognostic value for the disease-specific overall survival (P = 0.04). Our results suggest that intratumoral lymphatics play a greater role than peritumoral lymphatics in nodal metastasis of HNSCC and that tumor CD44 levels can predict sensitivity to radiation therapy. These parameters may be useful predictive and prognostic tools in the clinical management of HNSCC.