Relationship Between FAK and P53 Expression in Squamous Cell Carcinomas of the Larynx

Role of Focal Adhesion Kinase in Head and Neck Squamous Cell Carcinoma and Its Therapeutic Prospect

Head and neck cancers are one of the most prevalent cancers globally. Among them, head and neck squamous cell carcinoma (HNSCC) accounts for approximately 90% of head and neck cancers, which occurs in the oral cavity, oral pharynx, hypopharynx and larynx. The 5-year survival rate of HNSCC patients is only 63%, mainly because about 80–90% of patients with advanced HNSCC tend to suffer from local recurrence or even distant metastasis. Despite the more in-depth understanding of the molecular mechanisms underlying the occurrence and progression of HNSCC in recent years, effective targeted therapies are unavailable for HNSCC, which emphasize the urgent demand for studies in this area. Focal adhesion kinase (FAK) is an intracellular non-receptor tyrosine kinase that contributes to oncogenesis and tumor progression by its significant function in cell survival, proliferation, adhesion, invasion and migration. In addition, FAK exerts an effect on the tumor microenvironment, epithelial–mesenchymal transition, radiation (chemotherapy) resistance, tumor stem cells and regulation of inflammatory factors. Moreover, the overexpression and activation of FAK are detected in multiple types of tumors, including HNSCC. FAK inhibition can induce cell cycle arrest and apoptosis, significantly decrease cell growth, invasion and migration in HNSCC cell lines. In this article, we mainly review the research progress of FAK in the occurrence, development and metastasis of HNSCC, and put forward the prospects for the therapeutic targets of HNSCC.

Involvement of focal adhesion kinase in cellular proliferation, apoptosis and prognosis of laryngeal squamous cell carcinoma

OBJECTIVE

This study aimed to investigate the relationship between focal adhesion kinase expression and clinicopathological factors, cell apoptosis and proliferation, and overall survival, in laryngeal squamous cell carcinoma.

METHODS

Immunohistochemical staining was used to detect the expression of focal adhesion kinase and proliferating cell nuclear antigen in tissue samples. Apoptotic cells were assessed using the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labelling ('TUNEL') method.

RESULTS

The proportion of focal adhesion kinase expression was 73.26 per cent in tumour tissues, significantly greater than in normal tissues (p < 0.05), and was significantly related to laryngeal cancer clinical stage, lymph node metastasis and overall survival (p < 0.05). In the tumour cases assessed, up-regulation of focal adhesion kinase expression was significantly associated with decreased cell apoptosis and increased proliferation (p < 0.05).

CONCLUSION

These findings suggest that focal adhesion kinase may affect laryngeal squamous cell carcinoma progression through regulation of cell apoptosis and proliferation. Focal adhesion kinase expression is a major prognostic factor in laryngeal cancer patients.

In oral squamous cell carcinoma, high FAK expression is correlated with low P53 expression

Focal adhesion kinase (FAK) and p53 have been associated with metastatic activity and a poor prognosis in oral squamous cell carcinoma (OSCC). Recently, a feedback mechanism in which FAK regulates p53 has been proposed. The present study aims to determine the role of p53 in FAK regulation in these tumors. FAK and p53 expression was examined by immunohistochemistry in normal oral mucosa and in 67 oral squamous cell carcinomas. p16(INK4a) was also studied in view of its association with human papillomavirus infection. The association between FAK and p53 was subsequently analyzed. FAK expression in OSCCs was heterogeneous: 22 (33 %) cases showed weak expression, 16 (24 %) showed moderate expression, and 22 (33 %) cases showed high expression. Regarding p53, 31 of 67 (46 %) available tumor specimens showed negative staining, and 36 of 67 (54 %) showed positive nuclear staining for p53. FAK expression was inversely correlated with p53 expression (Fisher's exact test, p = 0.005). There was no association between p16(INK4a) and p53 or FAK expression. In conclusion, our results support the hypothesis that FAK activity might be involved in the down-regulation of p53 expression in OSCC.