Pathologic fracture in childhood and adolescent osteosarcoma: A single-institution experience

Precision Medicine Highlights Dysregulation of the CDK4/6 Cell Cycle Regulatory Pathway in Pediatric, Adolescents and Young Adult Sarcomas

Simple Summary

This review provides an overview of clinical features and current therapies in children, adolescents, and young adults (AYA) with sarcoma. It highlights the basic and clinical findings on the cyclin-dependent kinases 4 and 6 (CDK4/6) cell cycle regulatory pathway in the context of the precision medicine-based molecular profiles of the three most common types of pediatric and AYA sarcomas—osteosarcoma (OS), rhabdomyosarcoma (RMS), and Ewing sarcoma (EWS).

Abstract

Despite improved therapeutic and clinical outcomes for patients with localized diseases, outcomes for pediatric and AYA sarcoma patients with high-grade or aggressive disease are still relatively poor. With advancements in next generation sequencing (NGS), precision medicine now provides a strategy to improve outcomes in patients with aggressive disease by identifying biomarkers of therapeutic sensitivity or resistance. The integration of NGS into clinical decision making not only increases the accuracy of diagnosis and prognosis, but also has the potential to identify effective and less toxic therapies for pediatric and AYA sarcomas. Genome and transcriptome profiling have detected dysregulation of the CDK4/6 cell cycle regulatory pathway in subpopulations of pediatric and AYA OS, RMS, and EWS. In these patients, the inhibition of CDK4/6 represents a promising precision medicine-guided therapy. There is a critical need, however, to identify novel and promising combination therapies to fight the development of resistance to CDK4/6 inhibition. In this review, we offer rationale and perspective on the promise and challenges of this therapeutic approach.

Novel insights into the interaction between N6-methyladenosine methylation and noncoding RNAs in musculoskeletal disorders

BACKGROUND

Musculoskeletal disorder (MSD) are a class of inflammatory and degener-ative diseases, but the precise molecular mechanisms are still poorly understood. Noncoding RNA (ncRNA) N6-methyladenosine (m6A) modification plays an essential role in the pathophysiological process of MSD. This review summarized the interaction be-tween m6A RNA methylation and ncRNAs in the molecular regulatory mechanism of MSD. It provides a new perspective for the pathophysiological mechanism and ncRNA m6A targeted therapy of MSD.

METHODS

A comprehensive search of databases was conducted with musculoskeletal disorders, noncoding RNA, N6-methyladenosine, intervertebral disc degeneration, oste-oporosis, osteosarcoma, osteoarthritis, skeletal muscle, bone, and cartilage as the key-words. Then, summarized all the relevant articles.

RESULTS

Intervertebral disc degeneration (IDD), osteoporosis (OP), osteosarcoma (OS), and osteoarthritis (OA) are common MSDs that affect muscle, bone, cartilage, and joint, leading to limited movement, pain, and disability. However, the precise pathogenesis remains unclear, and no effective treatment and drug is available at present. Numerous studies confirmed that the mutual regulation between m6A and ncRNAs (i.e., microRNAs, long ncRNAs, and circular RNAs) was found in MSD, m6A modification can regulate ncRNAs, and ncRNAs can also target m6A regulators. ncRNA m6A modification plays an essential role in the pathophysiological process of MSDs by regulating the homeostasis of skeletal muscle, bone, and cartilage.

CONCLUSION

m6A interacts with ncRNAs to regulate multiple biological processes and plays important roles in IDD, OP, OS, and OA. These studies provide new insights into the pathophysiological mechanism of MSD and targeting m6A-modified ncRNAs may be a promising therapy approach.

Meta-analysis of the prognosis after surgical treatment of osteosarcoma complicated by pathologic fracture

AIM

To evaluate the prognosis of surgical treatment of osteosarcoma complicated by pathologic fracture.

MATERIALS AND METHODS

We searched articles in PubMed, Web of Science, and Embase for studies published up to January 1, 2022, that reported the surgical prognosis of osteosarcoma patients complicated with/without pathologic fracture. The specific outcome indicators used in the meta-analysis included the local recurrence rate (LRR), distant metastasis rate (DMR), overall survival (OS) rate and disease-free survival (DFS) rate after surgical treatment such as amputation or limb salvage in the pathologic fracture group and non-pathologic fracture group. Crude and adjusted Odds Ratio (OR) with 95% confidence intervals were used to compare data between the case group and control group. Fifteen studies and 3839 patients were included in the final meta-analysis.

RESULTS

The difference between the pathologic fractures group and the non-pathologic fracture group was not statistically significance in LRR analysis (OR = 1.27, 95% CI: 0.88-1.84, P > 0.05); however, a statistically significant difference was found between two groups in DMR (OR = 1.42, 95% CI: 1.03-1.95, P < 0.05). For survival rates, the following ORs were found: 3-year OS (OR = 1.71, 95% CI: 1.25-2.35, P < 0.05); 5-year OS (OR = 1.41, 95% CI: 1.06-1.87, P < 0.05); 3-year DFS (OR = 1.88, 95% CI: 1.20-2.94, P < 0.05); and 5-year DFS (OR = 1.49, 95% CI: 1.10-2.03, P < 0.05). The pooled estimate of OR is 1.48 (95% CI: 0.72-3.04, P > 0.05) for local recurrence and 1.82 (95% CI: 0.92-3.60, P > 0.05) for distant metastasis in the amputation group and the limb salvage group for osteosarcoma patients with pathologic fractures, respectively. Our analysis indicated that patients with a pathologic fracture have a higher risk of DMR after surgery, but there is no significant difference in LRR between patients with a pathologic fracture and without. Additionally, in osteosarcoma patients with a pathologic fracture, there was no difference in LDR or DMR between limb-salvage surgery and amputation.

CONCLUSION

Complicated with pathologic fracture is a negative prognostic indicator of osteosarcoma, and its poor survival rates (both OS and DFS) may be associated with a higher DMR. For osteosarcoma patients with pathologic fractures treated with standard treatment, LRR and DMR exhibit no significant difference between amputation and limb-salvage surgery.

Impact of Secondary Aneurysmal Bone Cysts on Survival of Patients with Enneking Stage IIB Extremity Osteosarcoma: A Propensity Score Matching Analysis

BACKGROUND

The clinicopathology of aneurysmal bone cysts (ABCs) secondary to osteosarcoma has not yet been reported. We conduct a retrospective review of ABCs secondary to osteosarcoma to characterize clinicopathology and influence on the survival of patients with Enneking stage IIB extremity osteosarcoma.

PATIENTS AND METHODS

A total of 300 patients with Enneking stage IIB extremity osteosarcoma were eligible for analysis. These cases were divided, according to the pathology of biopsy and magnetic resonance imaging (MRI), into ABCs group and no ABCs group. Patients (ABCs versus no ABCs) were compared using a 1:2 propensity score analysis to best match between groups. Clinicopathology and survival data were analyzed.

RESULTS

The total occurrence rate of secondary ABCs was 10.3%. A higher prevalence of pathological fractures was observed in the ABCs group (22.6%) compared with the no ABCs group (8.6%) (p = 0.032). Patients with ABCs were more likely to undergo amputation compared with patients without ABCs (p = 0.007). Those with secondary ABCs had poorer response to chemotherapy before and after propensity score matching (p = 0.006 and p = 0.048, respectively). Kaplan-Meier survival analysis showed that EFS and OS distributions were not significantly different between the two patient groups. ABCs were not significantly different in terms of EFS or OS in the multivariate analysis model (p > 0.05).

CONCLUSIONS

The presence of secondary ABCs was associated with increased occurrence rate of pathological fracture and high percentage of amputation. Moreover, patients with secondary ABCs had poorer response to chemotherapy. However, the presence of secondary ABCs did not influence survival of patients with Enneking stage IIB extremity osteosarcoma.

Clinical and Molecular Analysis of Pathologic Fracture-associated Osteosarcoma: MicroRNA profile Is Different and Correlates with Prognosis

BACKGROUND

MicroRNAs are small, noncoding RNAs that regulate the expression of posttranslational genes. The presence of some specific microRNAs has been associated with increased risk of both local recurrence and metastasis and worse survival in patients with osteosarcoma. Pathologic fractures in osteosarcoma are considered to be more the manifestation of a neoplasm with a more aggressive biological behavior than the cause itself of worse prognosis. However, this has not been proved at the biological or molecular level. Currently, there has not been a microRNA profiling study of patients who have osteosarcoma with and without pathologic fractures that has described differences in terms of microRNA profiling between these two groups and their correlation with biologic behavior.

QUESTIONS/PURPOSES

(1) In patients with osteosarcoma of the extremities, how do the microRNA profiles of those with and without pathologic fractures compare? (2) What relationship do microRNAs have with local recurrence, risk of metastasis, disease-specific survival, and overall survival in osteosarcoma patients with pathologic fractures?

METHODS

Between 1994 and 2013, 217 patients were diagnosed and treated at our institution for osteosarcoma of the extremities. Patients were excluded if (1) they underwent oncologic resection of the osteosarcoma at an outside institution (two patients) or (2) they were diagnosed with an extraskeletal osteosarcoma (29 patients) or (3) they had less than 1 year of clinical follow-up and no oncologic outcome (local recurrence, metastasis, or death) (four patients). A total of 182 patients were eligible. Of those, 143 were high-grade osteosarcomas. After evaluation of tumor samples before chemotherapy treatment, a total of 80 consecutive samples were selected for sequencing. Demographic and clinical comparison between the sequenced and non-sequenced patients did not demonstrate any differences, confirming that both groups were comparable. Diagnostic samples from the extremities of 80 patients with high-grade extremity osteosarcomas who had not yet received chemotherapy underwent microRNA sequencing for an ongoing large-scale osteosarcoma genome profiling project at our institution. Six samples were removed after a second look by a musculoskeletal pathologist who verified cellularity and quality of samples to be sequenced, leaving a total of 74 patients. Of these, two samples were removed as they were confirmed to be pelvic tumors in a second check after sequencing. The final study sample was 72 patients (11 patients with pathologic fractures and 61 without). Sequencing data were correlated with fractures and local recurrence, risk of metastasis, disease-specific survival, and overall survival through Kaplan-Meier analyses.

RESULTS

Several microRNAs were expressed differently between the two groups. Among the markers with the highest differential expression (edgeR and DESeq algorithms), Hsa-mIR 656-3p, hsa-miR 493-5p, and hsa-miR 381-3p were upregulated in patients with pathologic fractures, whereas hsa-miR 363, hsa-miR 885-5p, and has-miR 20b-5p were downregulated. The highest differential expression fracture and nonfracture-associated microRNA markers also distinguished groups of patients with different metastasis risk, a well as different disease-specific and overall survival. Furthermore, the profile of pathologic fractures demonstrated a higher differential expression for microRNA markers that were previously associated with a higher risk of metastasis and lower survival rates in patients with osteosarcoma.

CONCLUSIONS

In patients who have osteosarcoma, the microRNA profiles of those with pathologic fractures are different than of patients without pathologic fractures. The highest differential expression mircroRNA molecules in patients with pathologic fractures predict also higher risk of metastatic disease as well as worse disease-specific survival and overall survival. Furthermore, we found higher differential expression of microRNAs in the pathologic fracture group previously associated with poor prognosis. The higher risk of metastasis and poorer overall survival in patients with pathologic fractures is inherent to tumor aggressive biologic behavior. It is plausible that the fracture itself is not the direct cause of worse prognosis but another manifestation of tumor biologic aggressiveness. Identification of these molecules through liquid biopsies may help to determine which patients may benefit from surgery before fractures occur. The same technology can be applied to identify patterns of response to conventional chemotherapy, assisting in more specific and accurate systemic therapy.

LEVEL OF EVIDENCE LEVEL

III, prognostic study.