Effect of Irradiation on Malignant Tumour Invasion into Bone

Establishment of a xenograft model to explore the mechanism of bone destruction by human oral cancers and its application to analysis of role of RANKL

BACKGROUND

The molecular mechanism underlying bone invasion caused by oral squamous cell carcinoma (OSCC) is not well understood. To elucidate the molecular mechanism, the development of more suitable xenograft models mimicking human mandibular bone destruction by OSCC has been required.

MATERIALS AND METHODS

Human OSCC cell lines, HSC3, HSC3-C1, and HSC3-R2, were injected in the periosteal region of the mandible in athymic mice, and the bone destruction was analyzed. Receptor activators of nuclear factor κ-B ligand (RANKL) mRNA and protein expression levels were measured in the OSCC cell lines. Antibody that specifically neutralizes mouse RANKL and human RANKL, respectively, was injected into HSC3-cell-transplanted mice.

RESULTS

Transplantation of HSC3 cells induced mandibular bone destruction. Histological examination revealed numerous osteoclasts on the bone destruction surface. Fibroblastic cell intervention between the cancer nests and resorbing bone surface was observed in a similar fashion to those observed in human OSCC cases. The number of osteoclasts and fibroblasts was significantly correlated. Bone destruction induced by the transplantation of HSC3 cells was reduced by injection of an antibody that specifically neutralizes mouse RANKL. Transplantation of HSC3-R2 cells, which overexpresses RANKL, induced advanced bone destruction compared to that of HSC3-C1 cells, which only overexpress the empty vector.

CONCLUSIONS

We established a useful xenograft model for investigating the molecular mechanism underlying the bone destruction induced by OSCC in the jaw. This model will be used to investigate the precise roles of several cytokines synthesized by both cancer cells and fibroblastic cells in OSCC-associated bone destruction in the jaw.

Skull destruction from intracranial metastasis arising from pulmonary squamous cell carcinoma: a case report

Introduction

Squamous cell carcinoma of the lung represents 30% of all non-small cell lung carcinomas. It arises from dysplasia of squamous epithelium of the bronchi and is strongly associated with cigarette smoking. Squamous cell carcinoma of the lung is known to produce metastases in the brain parenchyma.

Case presentation

We present the case of an 80-year-old indigenous Australian man with an unusual presentation of metastatic carcinoma of the lung. The case demonstrated a squamous cell carcinoma of the lung with an intracranial metastatic lesion destroying the parietal bone and extending into the extracranial soft tissue. A visible deformity as a result of the metastasis was evident on physical examination and computed tomography demonstrated extensive bone destruction.

Conclusion

The authors were unable to find a case of this occurring from a squamous cell carcinoma of the lung anywhere in the world literature. The case report demonstrates an unusual disease presentation with a rare intracranial metastasis invading through the skull.