Type I collagenase expression and activity in the osteoblastic stromal cells of giant cell tumor of bone
Bibliographic record
Abstract
570 Giant cell tumor of bone (GCT) is a locally aggressive osteolytic tumor with metastasic potential. Its name is derived from the osteoclast-like multinucleated giant cells that are present in the tumor. In addition, two other cell types are present within GCT: mononucleated spindle-like stromal cells of osteoblastic origin, and round, CD68-positive monocytes. The stromal cells are considered the neoplastic component of GCT and are thought to promote the formation of the multinucleated giant cells. The latter have classically been implicated in bone destruction due to their morphological resemblance to osteoclasts. Evidence suggests that proteases, including members from the family of matrix metalloproteinases (MMPs), are involved in the collagen-degrading activity of the tumor. Type I collagen constitutes approximately 90% of the bone microenvironment, and the type I collagenases, MMP-1, MMP-8 and MMP-13 are capable of degrading the intact triple-helix of type I collagen, whereas other members of the MMP family are not. Here we report that the stromal cells of GCT produce type I collagenases and are capable of degrading type I collagen independent of the giant cells. GCT samples from primary tissue were collected with patient consent and stromal cells were isolated and grown in culture through a process of selective trypsinization. PCR, western blot analysis, and the use of a multiplex protein assay system revealed the presence of type I collagenases. Immunohistochemistry on paraffin-embedded tissue samples confirmed the presence of these collagenases in the stromal cells in vivo. The activity of these collagenases was determined by standardized collagenase degradation assays using stromal cell conditioned media. These results suggest that, contrary to popular belief, the stromal cells of GCT play a key role in bone destruction and that these cells act through an MMP-mediated mechanism that can be targeted to improve the clinical management of these tumors.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".