Correlations among three markers were described using the Spearman rank correlation test. Correlations between the expression of three markers and patient age, MIB-1 labelling index were estimated using the Mann-Whitney U test. All calculations and analyses were performed with SPSS 12.0 for Windows. Significance was selleck screening library considered to be P < 0.05. Results Expression of HIF-1α, MRP1 and MDR1 in human chordomas Different pattern of immunoreactivity was found as membranous or

cytoplasmic staining for MDR1 and MRP1, while cytoplasmic, part of nuclear positive for HIF-1α. MDR1 positive staining Selleck MK5108 was found in five (10%) of the 50 lesions which scored 1 (Figure 1E, F), and scored 0 in the remaining lesions. Thirteen of the 50 lesions were assigned to MRP1 score 0; three of the lesions scored 1; eighteen lesions scored 2; and sixteen lesions scored 3. Ten of the 50 lesions were assigned to

HIF-1α score 0; four of the lesions scored 1; fourteen lesions scored 2; and twenty-two lesions scored 3. As a consequence, 37 (74%) lesions expressed MRP1 with score ≥1; 16 (32%) lesions showed Sotrastaurin order strong expression with score 3 (Figure 1C, D). 40 (80%) lesions expressed HIF-1α with score ≥1; 22 (44%) lesions showed strong expression with score 3 (Figure 1A, B). Expression of HIF-1α in chordoma was much higher than that in nucleus pulposus; expressiong of MRP1 in chordoma was also much higher than that in nucleus pulposus; but expression of MDR1 in chordoma was not different from that in nucleus pulposus. (Table 1) Figure 1 Immunohistochemical staining of HIF-1α, MDR1 and MRP1 in chordoma, CM-319 and nucleus pulpous. With immunohistochemical staining, the expression of chemotherapy resistant proteins using primary antibody to HIF-1α (A, B, G), MDR1 (E, F, I) and MRP1 (C, D, H) was determined in chordoma (B, D, F) and CM-319 (A, C, E). Intense membrane and cytoplasmic staining of MRP1 (×400) and cytoplasmic and nuclus staining of HIF (×400). Negative immunostaining of MDR1 was found in chordoma and CM-319. In control, negative immunostaining of HIF-1, MRP1 and MDR1 (G, H, I) was found in nucleus pulposus.

Table 1 Expression of HIF-1α, MRP1 and MDR1 in chordoma tissue and nucleus pulposus tissue   positive (-)-p-Bromotetramisole Oxalate negative positive rate χ 2 P HIF-1α(n) chordoma 40 10 80% 18.55 <0.005 nucleus pulposus 3 12 20%     MRP1 (n) chordoma 37 13 74% 11.10 <0.005 nucleus pulposus 4 11 26.7%     MDR1 (n) chordoma 5 45 10% 0.343 >0.5 nucleus pulposus 3 12 20%     Correlation of antibody expression in chordomas tumors Using Kruskal-Wallis test, we examined the relationship among MDR1, MRP1 and HIF-1α. For spinal chordoma tumors, whether primary or recurrent, we found that the overall immunoreactivity score of MRP1 or HIF-1α was higher in cases showing expression of MDR1. There was no correlation between the expression of MDR1, MRP1, HIF-1α expression and patient age, gender.