05 level (two-tailed). ★Correlation was significant at the

0.01 level (two-tailed). Some level of MMP-9 expression was detected in the cytoplasm of the majority of the samples; 69% (33 of 48) of the cases showed high CB-839 in vitro tumour MMP-9 expression (moderate or strong), while only 4 of 48 cases (8%) tested AR-13324 clinical trial negative for MMP-9 expression. In all the specimens, stromal MMP-9 expression was detected, with 81% showing high expression. High expression of tumour and stromal MMP-9 were significantly associated with positive lymph node status (P < 0.01). High ColIV expression was observed in 73% (35 of 48) of the samples. Col IV expression was associated with positive lymph node status (P < 0.05), and Spearman’s analysis revealed that the expressions of MMP-2 and MMP-9 were negatively correlated

with ColIV expression (P < 0.01 and P < 0.001,respectively; Table 3). Table 3 Association between JIB04 expressions of MMP-2/MMP-9 and type IV collagen in patients with oral tongue cancer using Spearman’s correlation analysis Molecule   Type IV collagen MMP-2 R −0.365* MMP-9 R −0.568* R represents the coefficient of correlation. * Correlation was significant at the 0.05 level (two-tailed). Correlation of MMP-2, MMP-9 and ColIV expression with patient survival by univariate analysis Univariate analysis showed a statistically significant negative correlation between MMP-2 expression in the tumour cells and overall survival (Figure 2A–B), i.e. patients with high MMP-2 expression had a shorter survival than patients with low MMP-2 expression. The same result was observed for a subgroup of patients with MMP-9 positive (P < 0.001) (Figure 2C–D). In contrast, the relationship between overall survival and ColIV expression was inverse (P < 0.01) (Figure 2E), i.e. patients with low ColIV expression had a shorter

survival than did patients with high ColIV expression. Figure 2 Kaplan-Meier survival curves for stromal and tumour expression of MMP-2 (A and B), MMP-9 (C and D) and ColIV (E). The high expression of MMP-2, MMP-9, and type PIK3C2G IV collagen (low and high) in tumour was significantly associated with shorter OS (P < 0.001). All samples were positive for stromal MMP-9. Patients with moderate or less expression of stromal MMP-9 have longer OS compared with those with strong expression. Discussion The distribution of ColIV in the BM of normal tongue mucosa is compatible with its corresponding functions. When pathological stimulating factors act on tongue mucosa, ColIV attached to the BM can effectively prevent harmful substances from penetrating the BM to the lamina propria [19–21]. Our present study shows, ColIV gradually reduced, was fragmented, collapsed, or even dissolved completely, thus providing channels for cancer cells to invade the lamina propria. ColIV also formed membrane-like structures in tumour tissue, but it became thick and sparse. In well-differentiated carcinomas, we observed that the thick and sparse ColIV around the cancer nests.