Immunohistochemical Investigation of Predictive Biomarkers for Mandibular Bone Invasion in Oral Squamous Cell Carcinoma

Assessment of Bone Invasion and Its Correlation With Brandwein-Gensler Criteria in Oral Squamous Cell Carcinoma

Background The most prevalent form of head-neck cancer is squamous cell carcinoma (SCC). Apart from all sites like the tongue, labial mucosa, and buccal mucosa, the prevalence of oral squamous cell carcinoma (OSCC) is more common in gingivobuccal sulcus due to the habit of keeping tobacco quid. With regards to anatomical relationships in the mouth and proximity to bone, OSCC invades the maxilla and mandible. However, bone invasion significantly influences the pathological staging of OSCC. Histological parameters such as Brandwein-Gensler worst pattern of invasion (WPOI), lymphocytic host response (LHR), and perineural invasion (PNI) hold significance for determining the need for adjuvant therapy. This study aims to correlate Brandwein-Gensler Criteria (BGC) with bone invasion and also to include the bone invasion criteria as a prognostic parameter in OSCC. This study aimed to assess bone invasion and correlate it with Brandwein-Gensler criteria in OSCC. Methods The research was conducted retrospectively, analyzing 65 cases of OSCC that underwent surgical intervention. Data was gathered from the Oral Pathology department's archives at Sharad Pawar Dental College (SPDC), Wardha. Pathologists assessed bone invasion without the knowledge of other factors to minimize bias. Subsequently, the cases were classified into well-differentiated (WDSCC), moderately differentiated (MDSCC), and poorly differentiated squamous cell carcinomas (PDSCC) based on histological grading, followed by the evaluation of WPOI, LHR, and PNI using the Brandwein-Gensler risk scoring system. Results This study found a notable association between bone invasion and BGC, with a calculated significance level of p = 0.047. LHR shows patterns as 1, 2, and 3. There were five (7.6%) cases with pattern III, 45 (69.23%) cases with pattern II, and 15 (23.08%) cases with pattern I. Similarly, PNI is scored as 0, 1, and 3. There were seven (10.77%) cases with score 3, 17 (26.15%) with score 1, and 41 (63.03%) with score 0. In the case of the WOPI, which is classified as patterns I to V, there were seven (10.77%) cases with pattern V, 27 (41.54%) cases with pattern IV, 23 (35.38%) cases with pattern III, and eight (12.231%) cases with pattern II, whereas no cases were noted with pattern I. Conclusion Although bone invasion and BGC are independent parameters, the BGC score should be considered in treatment planning. Patients with bone invasion and those with a higher BGC score should be strongly considered for adjuvant treatment.

BMSC-HNC Interaction: Exploring Effects on Bone Integrity and Head and Neck Cancer Progression

In recent research, the tumor microenvironment has been shown to attract mesenchymal stromal cells (MSCs), which is of particular interest due to its implications for cancer progression. The study focused on understanding the interaction between bone marrow-derived MSCs (BMSCs) and head and neck cancer (HNC) cells. This interaction was found to activate specific markers, notably the osteogenic marker alkaline phosphatase and the oncogene Runx2. These activations corresponded with the release of collagenase enzymes, MMP9 and MMP2. To gain insights into bone resorption related to this interaction, bovine bone slices were used, supporting the growth of "heterogeneous spheroids" that contained both BMSCs and HNC cells. Through scanning electron microscopy and energy-dispersive X-ray (EDX) analysis, it was observed that these mixed spheroids were linked to a notable increase in bone degradation and collagen fiber exposure, more so than spheroids of just BMSCs or HNC cells. Furthermore, the EDX results highlighted increased nitrogen content on bone surfaces with these mixed clusters. Overall, the findings underscore the significant role of BMSCs in tumor growth, emphasizing the need for further exploration in potential cancer treatment strategies.

Jaw Bone Invasion of Oral Squamous Cell Carcinoma Is Associated with Osteoclast Count and Expression of Its Regulating Proteins in Patients and Organoids

AIMS

Oral squamous cell carcinoma (OSCC) frequently invades the jaw. The exact mechanism of bone invasion remains unclear. This study investigates (premature) osteoclasts and the expression of its differentiation regulating proteins RANKL, OPG and RANK in patients with OSCC.

METHODS

Resection specimens from OSCC patients were divided into NI group (No Invasion), E group (Erosion) or I group (bone Invasion). Tissue sections were stained with Cathepsin K (osteoclast-counting), RANKL, OPG and RANK. The staining intensity was scored on different regions of the tumor: front, center, back and normal mucosa. Immunohistochemistry and qPCR for RANKL/OPG/RANK were performed on five head and neck squamous cell carcinoma (HNSCC) organoids.

RESULTS

The mean number of osteoclasts (I group) and premature osteoclasts (E group) was significantly higher compared to the NI group (p = 0.003, p = 0.036). RANKL expression was significantly higher in the tumor front and tumor center compared to normal mucosa (all groups). In the I group, RANKL and RANK expression was significantly higher in the tumor front compared to the tumor back and there was a trend of higher RANKL expression in the tumor front compared to the E group and NI group. qPCR showed a 20-43 times higher RANKL mRNA expression in three out of five tumor organoids compared to a normal squamous cell organoid line. There was no correlation between protein and mRNA expression in the HNSCC organoids.

CONCLUSIONS

These findings suggest that OSCCs induce bone invasion by stimulating osteoclast activation by regulating the production of RANKL and RANK proteins.

Significance of cancer stroma for bone destruction in oral squamous cell carcinoma using different cancer stroma subtypes

Stromal cells in the tumor microenvironment (TME) can regulate the progression of numerous types of cancer; however, the bone invasion of oral squamous cell carcinoma (OSCC) has been poorly investigated. In the present study, the effect of verrucous SCC-associated stromal cells (VSCC-SCs), SCC-associated stromal cells (SCC-SCs) and human dermal fibroblasts on bone resorption and the activation of HSC-3 osteoclasts in vivo were examined by hematoxylin and eosin, AE1/3 (pan-cytokeratin) and tartrate-resistant acid phosphatase staining. In addition, the expression levels of matrix metalloproteinase (MMP)9, membrane-type 1 MMP (MT1-MMP), Snail, receptor activator of NF-κB ligand (RANKL) and parathyroid hormone-related peptide (PTHrP) in the bone invasion regions of HSC-3 cells were examined by immunohistochemistry. The results suggested that both SCC-SCs and VSCC-SCs promoted bone resorption, the activation of osteoclasts, and the expression levels of MMP9, MT1-MMP, Snail, RANKL and PTHrP. However, SCC-SCs had a more prominent effect compared with VSCC-SCs. Finally, microarray data were used to predict potential genes underlying the differential effects of VSCC-SCs and SCC-SCs on bone invasion in OSCC. The results revealed that IL1B, ICAM1, FOS, CXCL12, INS and NGF may underlie these differential effects. In conclusion, both VSCC-SCs and SCC-SCs may promote bone invasion in OSCC by enhancing the expression levels of RANKL in cancer and stromal cells mediated by PTHrP; however, SCC-SCs had a more prominent effect. These findings may represent a potential regulatory mechanism underlying the bone invasion of OSCC.

Transforming growth factor-β-regulated fractalkine as a marker of erosive bone invasion in oral squamous cell carcinoma

Patients with oral squamous cell carcinoma (OSCC) bone invasion are surgically treated with bone resection, which results in severe physical and psychological damage. Here, we investigated the potential of fractalkine (CX3CL1), which is regulated by transforming growth factor (TGF-β), as a novel biomarker for correct prediction and early detection of OSCC-associated bone invasion. TGF-β knockdown and treatment with a TGF-β-neutralizing antibody decreased the level of fractalkine in the culture media of HSC-2 and YD10B OSCC cells. Treatment with a fractalkine-neutralizing antibody reduced TGF-β-stimulated invasion by HSC-2 and YD10B cells. Fractalkine treatment increased the viability, invasion, and uPA secretion of both OSCC cell lines. Furthermore, OSCC cell bone invasion was assessed following subcutaneous inoculation of wild-type or TGF-β knockdown OSCC cells in mouse calvaria. TGF-β knockdown prevented erosive bone invasion, reduced the number of osteoclasts at the tumor-bone interface, and downregulated fractalkine expression in mouse tumor tissues. Our results indicate that the production of fractalkine is stimulated by TGF-β and mediates TGF-β-induced cell invasion in several OSCC cell lines showing an erosive pattern of bone invasion. Fractalkine may be a useful predictive marker and therapeutic target for OSCC-induced bone destruction.