ABSTRACT
Background: Tissue micro-array enables the analysis of a large number of tissues simultaneously. Widespread use of this technology is hampered by the high cost of commercial array instruments. We describe our experience of constructing tissue micro-array in a simple method using easily available and inexpensive instruments. Materials and Methods: We used an 11-19 gauge (G) bone marrow trephine biopsy needle/ small sized slotted screwdriver to punch holes in the wax blocks. Cores were taken from donor tissue blocks using a bone marrow trephine biopsy needle and arrayed into host paraffin wax blocks. A detailed database was constructed for each array constructed. Results: The array blocks were used over a period of one year as internal control for immunohistochemistry (IHC), quality control and research. It took about 10 minutes to construct a nine-dot array and about one hour for a 56-dot array. During IHC, the average loss of control dots was less than one per cent. We did not see any loss of antigenicity in the control sections even after four weeks storage. Discussion: Tissue array construction by the technique described here is inexpensive and reliable alternative to automated instruments. Because it is easy to modify the arrays by varying the core size, it is easy to adapt this to individual labs and requirements. We recommend using blocks with cores in 3 × 3 to 5 × 4 grids as controls in IHC and for standardizing antibodies and array blocks with a larger number of cores for research.
ABSTRACT
Background and purpose:The chemokine,CXCL12 and its receptor,CXCR4,have recently been shown to play an important role in the metastasis of several kinds of carcinoma. It also has been demonstrated that VEGF regulates both the expression of CXCR4 and invasiveness in cancer cell. Our aim was to study the expression of CXCR4,VEGF in osteosarcoma and the correlation between these two factors and distant metastasis. Methods: The immunohistochemical staining SP method was used to detect the expression of CXCR4 and VEGF in 56 cases of osteosarcoma. We analyzed the correlation between the expression of CXCR4 and VEGF,and the correlation between the expression of CXCR4,VEGF and clinical stage,the level of ALP. The patients were followed up for 2 years. Results:There was signifi cant correlation between the expression of CXCR4 and VEGF in 56 cases(r=5.678,P=0.02). Univariate analysis showed a signifi cant correlation between the expression of CXCR4,VEGF and clinical tumor stage(P=0.026),and no correlation between the expression of these two factors and age,sex and serum ALP level. 31 cases had metastasis in two years in a total of 56 follow-up cases,and the expression of CXCR4 and VEGF was associate with metastasis(P=0.018 and P=0.022,respectively). Conclusion:VEGF can upregulate tumor angiogenesis and promote tumor metastasis to specific organ by increasing expression of CXCR4.The increasing expression of CXCR4 and VEGF is useful to predict metastasis and prognosis of osteosarcoma.