Quantitative assessment of myofibroblast in severe dysplasia, microinvasion and oral squamous cell carcinoma: an immunohistochemical study

The Immune Cells in the Development of Oral Squamous Cell Carcinoma

A still unresolved issue surrounding tumor formation concerns the role that the immune system plays in preventing the formation and progression of neoplasia, including oral squamous cell carcinoma (OSCC). Antitumor immunity has historically been seen as a critical barrier for cancer cells to develop, grow and spread, and this can be modulated using immunotherapies to achieve antitumor clinical responses. However, it has recently become clear that tumor-associated immunity, particularly the inflammatory microenvironment, has the paradoxical effect of enhancing tumorigenesis and progression. In this review, we discuss the multifaceted function of infiltrating immune cells in suppressing or promoting premalignancy and cancer. In particular, we report on the evidence supporting a role for T lymphocytes, dendritic cells, macrophages, and neutrophils in the development and progression of oral potentially malignant disorders (OPMD) and OSCC. We also draw attention to the clinical relevance of immune cell phenotypes and associated molecules for use as biomarkers and to the translatability of current research findings to improve classification systems and precision medicine in patients with OSCC.

Tumor microenvironment: an evil nexus promoting aggressive head and neck squamous cell carcinoma and avenue for targeted therapy

Head and neck squamous cell carcinoma (HNSCC) is a very aggressive disease with a poor prognosis for advanced-stage tumors. Recent clinical, genomic, and cellular studies have revealed the highly heterogeneous and immunosuppressive nature of HNSCC. Despite significant advances in multimodal therapeutic interventions, failure to cure and recurrence are common and account for most deaths. It is becoming increasingly apparent that tumor microenvironment (TME) plays a critical role in HNSCC tumorigenesis, promotes the evolution of aggressive tumors and resistance to therapy, and thereby adversely affects the prognosis. A complete understanding of the TME factors, together with the highly complex tumor-stromal interactions, can lead to new therapeutic interventions in HNSCC. Interestingly, different molecular and immune landscapes between HPV^+ve and HPV^-ve (human papillomavirus) HNSCC tumors offer new opportunities for developing individualized, targeted chemoimmunotherapy (CIT) regimen. This review highlights the current understanding of the complexity between HPV^+ve and HPV^-ve HNSCC TME and various tumor-stromal cross-talk modulating processes, including epithelial-mesenchymal transition (EMT), anoikis resistance, angiogenesis, immune surveillance, metastatic niche, therapeutic resistance, and development of an aggressive tumor phenotype. Furthermore, we summarize the recent developments and the rationale behind CIT strategies and their clinical applications in HPV^+ve and HPV^-ve HNSCC.

Comparison of expression of myofibroblasts in normal oral mucosa, oral epithelial dysplasia, and oral squamous cell carcinoma using α-SMA and vimentin: An immunohistochemical study

Background:

Myofibroblasts are thought to play critical roles in inflammation, growth, repair, premalignancy, and malignancy. This study was done to evaluate, compare and co- relate the progressive increase in the immunohistochemical expression of myofibroblasts in normal oral mucosa, epithelial dysplasia, and oral squamous cell carcinoma (OSCC). To compare and co-relate the expression of myofibroblasts in normal oral mucosa, epithelial dysplasia, and oral squamous cell carcinoma. To co-relate the progressive increase in myofibroblasts expression in normal oral mucosa, epithelial dysplasia, and oral squamous cell carcinoma.

Materials and Method:

Forty-nine paraffin-embedded tissue blocks with 7 cases of normal oral mucosa, 21 cases of epithelial dysplasia, and 21 diagnosed cases of OSCCs were studied. The samples were subjected to heat-induced antigen retrieval methods followed by staining using primary mouse monoclonal antibodies against α-smooth muscle actin (SMA) and vimentin. Staining index of all the sections was calculated. Statistical analysis was performed using the Kruskal–Wallis test, Mann–Whitney U test, and Chi-square test. Values of P less than or equal to 0.05 (P ≤ 0.05) were considered statistically significant.

Results:

Statistically significant staining index was obtained by α-SMA and vimentin between normal oral mucosa, epithelial dysplasia, and OSCC.

Conclusion:

Myofibroblast may play a role only during initial tumorigenesis that is the conversion of severe dysplasia into OSCC.

Effect of tumor microenvironment on pathogenesis of the head and neck squamous cell carcinoma: a systematic review

The tumor microenvironment (TME) is comprised of many different cell populations, such as cancer-associated fibroblasts and various infiltrating immune cells, and non-cell components of extracellular matrix. These crucial parts of the surrounding stroma can function as both positive and negative regulators of all hallmarks of cancer development, including evasion of apoptosis, induction of angiogenesis, deregulation of the energy metabolism, resistance to the immune detection and destruction, and activation of invasion and metastasis. This review represents a summary of recent studies focusing on describing these effects of microenvironment on initiation and progression of the head and neck squamous cell carcinoma, focusing on oral squamous cell carcinoma, since it is becoming clear that an investigation of differences in stromal composition of the head and neck squamous cell carcinoma microenvironment and their impact on cancer development and progression may help better understand the mechanisms behind different responses to therapy and help define possible targets for clinical intervention.

A Comparative Immunohistochemical Study of Presence and Distribution Pattern of Stromal Myofibroblast in Oral Dysplasia and in Different Grades of Oral Squamous Cell Carcinoma

Aims and Objectives:

Squamous cell carcinoma (SCC) is a common oral malignancy with a poor survival rate. Early tumorigenesis is marked by transdifferentiation of fibroblasts to myofibroblasts (MFs), which is supported by growth factors and cytokines expressed by tumor cells. The expression of alpha-smooth muscle actin (αSMA) marker correlates with the activation of MFs. This study was undertaken to compare the frequency and distribution of αSMA immunoexpression in oral epithelial dysplasia (OED) and OSCC.

Materials and Methods:

This study was conducted on samples collected from patients with oral epithelial dysplasia and oral SCC who visited Rajarajeswari Dental College and Hospital, Bengaluru. Tissue sections were subjected to Immunohistochemistry using αSMA marker, and cells were counted. The obtained data was subjected to Kruskal–Wallis test and Mann–Whitney U-test.

Results:

On performing Kruskal–Wallis test and Mann–Whitney U-test between the three groups (normal oral mucosa, OED, and OSCC) statistically significant result was found in the frequency between OED and OSCC and between normal tissue and OSCC. On comparing the distribution pattern, statistically significant result was found between OED and OSCC and between normal tissue and OSCC.

Conclusion:

The expression of MFs increases as the disease progresses from high-grade epithelial dysplasia to invasive OSCC. Poorly differentiated SCC showed more attendance of positive MFs in the stroma than other grades of OSCC. The rise in the number of αSMA-positive MFs and change in distribution pattern in OSCC can be associated with tumor invasive characteristics. Thus, the proliferation of MFs may be used as a stromal marker of premalignancy and malignancy.

Myofibroblasts in oral potentially malignant disorders: Is it related to malignant transformation?

In oral cancer, acquisition of α-smooth muscle actin (α-SMA)-positive fibroblasts, known as myofibroblasts or carcinoma-associated fibroblasts (CAF), is an important event for progression and metastasis. However, the contribution of myofibroblasts in oral potentially malignant disorders (OPMD) remains controversial. This systematic review provides evidence that immunodetection of myofibroblasts may identify oral submucous fibrosis (OSMF) with high risk of malignant transformation, but does not represent an auxiliary tool to predict the malignant potential of leukoplakia and erythroplakia, the most common OPMD.

Microenvironmental regulation of the progression of oral potentially malignant disorders towards malignancy

Oral potentially malignant disorders (OPMD) develop in a complex tissue microenvironment where they grow sustainably, acquiring oral squamous cell carcinoma (OSCC) characteristics. The malignant tumor depends on interactions with the surrounding microenvironment to achieve loco-regional invasion and distant metastases. Unlike abnormal cells, the multiple cell types in the tissue microenvironment are relatively stable at the genomic level and, thus, become therapeutic targets with lower risk of resistance, decreasing the risk of OPMD acquiring cancer characteristics and carcinoma recurrence. However, deciding how to disrupt the OPMD and OSCC microenvironments is itself a daunting challenge, since their microenvironments present opposite capacities, resulting in diverse consequences. Furthermore, recent studies revealed that tumor-associated immune cells also participate in the process of differentiation from OPMD to OSCC, suggesting that reeducating stromal cells may be a new strategy to prevent OPMD from acquiring OSCC characteristics and to treat OSCC. In this review, we discuss the characteristics of the microenvironment of OPMD and OSCC as well as new therapeutic strategies.