Immuno-Oncology Integrative Networks: Elucidating the Influences of Osteosarcoma Phenotypes

Osteosarcoma in a Teenage Athlete With a Swollen Knee Joint

Osteosarcoma is a malignant mesenchymal tumour. This primarily manifests in the formation of immature osteoid cells by tumour cells. Osteosarcoma is the most common primary bone tumour in children and adolescents. It tends to occur in the metaphysis of long shafts, shows osteoblastic differentiation, and produces malignant osteoid material. We present the case of a 17-year-old male who presented to our clinic who had left knee pain for a few days. An initial radiograph of the knee joint revealed a lytic lesion in the proximal tibia and further imaging was advised. During a follow-up visit, the patient had worsening pain and had a computerized tomography scan of the left knee, confirming osteosarcoma on the lateral side of the left tibia. He was referred to the orthopaedic department, where a biopsy was performed, to confirm the diagnosis of osteosarcoma. The patient was commenced on chemotherapy due to metastatic disease and has so far tolerated therapy well.

Expression of E-cadherin and N-cadherin in Epithelial-to-Mesenchymal Transition of Osteosarcoma: A Systematic Review

Osteosarcoma (OS) is a debilitating cancer of the bone that commonly afflicts the young and old. This may be de novo or associated with tumorigenic syndromes. However, many molecular mechanisms are still being uncovered and may offer greater avenues for screening and therapy. Cadherins, including E-cadherin and N-cadherin/vimentin, are involved in epithelial-to-mesenchymal transmission (EMT), which is key for tumor invasion. A study reviewing the relationship between OS and cadherins might elucidate a potential target for therapy and screening. A robust literature review was conducted by searching PubMed with the keywords "osteosarcoma", "cadherin", "e-cadherin" and "n-cadherin". Of a preliminary 266 papers, 25 were included in the final review. Review articles and those without primary data were excluded. Loss of E-cadherin is noted in metastatic cell lines of osteosarcoma. Overexpression of E-cadherin or knockout of N-cadherin/vimentin results in loss of metastatic potential. There are several methods of gene knockout, including CRISPR-Cas9 gene editing, viral vector insertion with micro RNA complementary to long noncoding RNA within gene segments, or proteomic editing. Screening for EMT and genetic treatment of EMT is a possible avenue for the treatment of refractory osteosarcoma. Several studies were conducted ex vivo. Further testing involving in vitro therapy is necessary to validate these methods. Limitations of this study involve a lack of in vivo trials to validate methods.

The Heterogeneity of Osteosarcoma: The Role Played by Cancer Stem Cells

Osteosarcoma is the most common bone sarcoma and is one of the cancer entities characterized by the highest level of heterogeneity in humans. This heterogeneity takes place not only at the macroscopic and microscopic levels, with heterogeneous micro-environmental components, but also at the genomic, transcriptomic and epigenetic levels. Recent investigations have revealed the existence in osteosarcoma of cancer cells with stemness properties. Cancer stem cells are characterized by their specific phenotype and low cycling capacity, and are linked to drug resistance, tumour growth and the metastatic process. In addition, cancer stem cells contribute to the enrichment of tumour heterogeneity. The present manuscript will describe the main characteristic features of cancer stem cells in osteosarcoma and will discuss their impact on maintaining tumour heterogeneity. Their clinical implications will also be briefly addressed.

The possible role of insulin-like growth factor-1 in osteosarcoma

Osteosarcoma (OS) is a common malignant tumor of bone, of which clear understanding of molecular pathologic process is not yet possible. Insulin-like growth factor-1 (IGF-1) is a hormone that plays vital role in development and function of many tissues. Unfortunately, IGF-1 and its receptor (IGF-1R)'s over-expression have been implicated in carcinogenesis, and indicated to constitute a risk factor for the development of multiple human cancers, including OS. Increased levels of IGF-1 and IGF-1R have been reported in OS, leading to cancer progression through transformation, proliferation, pro-metastasis, and decreased susceptibility to apoptosis. Over-expression of IGF-1/IGF-1R signaling also contributes to tumor cell survival, metastasis, and resistance to chemotherapeutic drugs. IGF-1 has been included as an OS marker recently, and targeting IGF-1 is an interesting and promising approach in OS therapeutics. However more investigations with clinical trials are necessary to validate the use of drugs against IGF-1 that may provide a basis for new therapeutic approaches to treat this devastating disease. This review article focused on the role of IGF-1/IGF-1R in OS progression and therapeutic aspects of OS targeting IGF-1.