RESUMEN
Background and purpose: p21-activated kinase 5 (PAK5) is a recently identified member of PAKs that regulate many intracellular processes such as cytoskeleton remodeling, cell proliferation, cell differentiation, gene transcription and cell apoptosis. Recently, studies found that PAK5 was overexpressed in some cancer such as gastric and colon cancer. However, the expression status and biological function of PAK5 in osteosarcoma are not clearly known. The objective of this study was to investigate the expression of PAK5 in osteosarcoma tissue and their relationships with the prognosis of osteosarcoma. Methods: The expression of PAK5 was detected by using immunohistochemical method in 92 specimens of human osteosarcoma tissues and 33 cases of osteoclastoma tissue, respectively. Results: The positive rate of PAK5 was 71.7% (66/92) in all the 92 cases of osteosarcoma. PAK5 expressions were not related to clinical variables such as gender, age, tumor location, tumor size, histological type and local recurrence, but signiifcantly related to Enneking grade, tumor cell necrosis rate and lung metastasis, and the high expression of PAK5 may reduce the efifciency of chemotherapy. Survival analysis indicated that high expression of PAK5 correlated with poor prognosis of patients with osteosarcoma. Univariate survival analysis showed that the signiifcant prognostic factors were tumor size, Enneking grade, local recurrence, lung metastasis and expression levels of PAK5. COX multivariate regression identified that the PAK5 expression levels (P=0.001) and lung metastasis (P=0.015) were independent prognostic factors of patients with osteosarcoma. Conclusion:The positive expressions of PAK5 closely correlate with Enneking grade, tumor cell necrosis rate and lung metastasis. Detection of PAK5 may be used as a molecular marker for prognosis of osteosarcoma. The high expression of PAK5 may reduce the efifciency of chemotherapy.
RESUMEN
PURPOSE: The purpose of this meta-analysis was to evaluate the predicting value of fluorine-18-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG PET-CT) in the assessment of histological response to neoadjuvant chemotherapy in patients with osteosarcomas. METHODS: A detailed search was made in MEDLINE, EMBASE and the Web of Knowledge for relevant original articles published in English; methodological quality of the included studies were also assessed. Two reviewers extracted data independently. Sufficient data was presented to construct a 2 × 2 contingency table. Pooled sensitivity and specificity, positive and negative likelihood ratios were estimated. A summary receiver operating characteristic curve (SROC) was constructed with the Moses' constant of linear model. A χ(2) test was performed to test for heterogeneity. RESULTS: Eight studies comprising 178 patients met the inclusion criteria. The pooled sensitivity and specificity for standardized uptake values (SUV) after chemotherapy (SUV2) ≤ 2.5 were 0.734 (95% CI, 0.537-0.867) and 0.864 (95% CI, 0.510-0.975), for the ratio of standardized uptake values after (SUV2) to before (SUV1) chemotherapy SUV 2:1 ≤ 0.5 were 0.690 (95% CI, 0.497-0.833) and 0.653 (95% CI, 0.492-0.786), the positive and negative likelihood ratio (LR+/LR-) for SUV2 ≤ 2.5 were 5.397 (95% CI, 1.169-24.920) and 0.308 (95% CI, 0.165-0.577), for SUV 2:1 ≤ 0.5 were 1.989 (95% CI, 1.145-3.457) and 0.475 (95% CI, 0.247-0.915). There was no significant difference between-study heterogeneity for either LR + or LR- in any of these analyses. The area under the SROC curve for SUV2 ≤ 2.5 and SUV 2:1 ≤ 0.5 were 0.81 and 0.72, respectively. CONCLUSIONS: The present meta-analysis showed that 18F-FDG PET-CT scan, as measured by the SUV before and after treatment, SUV2 ≤ 2.5 and SUV 2:1 ≤ 0.5 are valuable for predicting the histological response to chemotherapy. SUV2 ≤ 2.5 have better predicting performance than SUV 2:1 ≤ 0.5.
