ALDH1 and CD44 immunoexpression as prognostic indicators of invasion and metastasis in oral squamous cell carcinoma

Author(s)

Rafael Carneiro Ortiz

• Document type: Master's Dissertation
• Press: Bauru.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Bauru (FOB/SDB)
• Defense date: 2017-10-04

Examining board members

Camila de Oliveira Rodini Pegoraro; Vanessa Soares Lara; Maria Renata Sales Nogueira; Elcia Maria Varize Silveira

• Advisor: Camila de Oliveira Rodini Pegoraro

Abstract

Oral squamous cell carcinoma (OSCC) is one of the most common cancer in the head and neck and results in high morbidity and mortality annually, being the worst prognosis related to the presence of metastasis in cervical lymph nodes. Metastasis has been associated with a subpopulation of tumor cells, called cancer stem cells (CSCs), which consists of a small population with stem-like cells properties, higher rate of migration and metastatic potential compared to other ordinary tumor cells from the tumor bulk. The aim of present study was to evaluate the immunoexpression of the CSC markers ALDH1 and CD44 in primary sites of OSCC and corresponding metastatic lymph nodes, by means of immunohistochemistry. The immunolabeling was further correlated with clinicopathological data. Archived Formalin-fixed, Paraffin-embedded tumor tissue specimens (n=50) and corresponding metastatic lymph nodes (n=25) were obtained from 50 patients with OSCC after surgical treatment. CD44 and ALDH1 immunostaining were semi-quantitatively scored according to the proportion and intensity of positive cells within the invasive front and metastatic cervical lymph nodes as a whole. The percentage of ALDH1 and CD44 positive tumor cells as well as immunostaining intensity was graded and a combined score, ranging from 0 to 9 (ALDH1) or 0 to 12 (CD44), was obtained by multiplying both parameters. Next, combined scores were dichotomized into a final score classified as low (ALDH1 2; CD44 4) or high (ALDH1> 2; CD44> 4) immunoexpression. ALDH1 and CD44 immunoexpression was detected in both primary and metastatic tumor sites, although with different immunolabeling pattern. ALDH1-positive tumor cells consisted of scattered patches and no immunoexpression was observed within keratin pearls. Conversely, CD44 immunopositivity was more homogeneous and widely distributed, with higher labeling in peripheral areas of the tumor islands within the tumor invasion front. Although not statistically significant, the means of ALDH1high (p= 0.0985) and CD44high (p= 0.1632; Mann- Whitney post-test) immunoexpression were higher in metastatic lymph nodes compared to primary tumors. ALDH1high was positively associated (p= 0.0184) with perivascular invasion, while CD44high was positively associated (p= 0.0186; Fishers Exact Test) with metastasis (N+). Five-year survival rates tended to be lower in patients with ALDH1high immunoexpression compared to ALDH1low, although with no statistical significance (p= 0.1303). In summary, the present study revealed that CD44 is highly labeled in tumor cell from metastatic sites, being associated with lymph node metastasis, while ALDH1 high immunostaining was associated with perivascular invasion. Altogether, it suggests that immunoexpression of CD44 and ALDH1 links the cancer stem cell phenotype with OSCC invasion and metastasis. (AU)

• FAPESP's process: 15/06945-2 - Differential and comparative immunohistochemical analysis between primary OSCC and corresponding metastatic lesions
• Grantee: Rafael Carneiro Ortiz
• Support Opportunities: Scholarships in Brazil - Master