Research on Microvessel Density and its Relationship with Carcinoma-associated Fibroblasts in Salivary Adenoid Cystic Carcinoma
|School||Dalian Medical University|
|Keywords||adenoid cystic carcinoma carcinoma-associated fibroblasts microvessel density angiogenesis|
Objectives: Salivary gland adenoid cystic carcinoma (AdCC) is a commonmalignant tumor in the oral and maxillofacial region. Although growing slowly, itshows a high incidence of local invasion and distant metastasis. Invasion and metastasisof solid tumors are largely dependent on the continued angiogenesis in tumor tissues.Microvessel density (MVD) is an important indicator of angiogenesis. Recent studieshave shown that carcinoma-associated fibroblasts (CAFs) are important stromal cells intumor microenvironment. CAFs can secret cytokines and extracellular matrix, whichinduce angiogenesis. Our previous study has proved that CAFs exists in salivary glandAdCC. However, further investigation is necessary for the relationship between CAFsand MVD in salivary gland AdCC. The objectives of the present study are to examinewhether MVD is increased in salivary gland AdCC. If MVD is increased, we willexplore the relationship between MVD and CAFs.Materials and Methods: The tissue specimens of18cases of normal salivarygland and16cases of salivary gland AdCC were obtained from Department ofstomatology surgery, Dalian Medical University. The expression of VIM, α-SMA andCD34in these samples were detected by standard immunohistochemistry technique.The average Integral Optical Density（IOD）value of VIM and α-SMA was analyzed byImage-Pro Plus6.0software. Vascular endothelial cells were highlighted by theanti-CD34antibody, and the “hot spot” method which is founded by Weidner was usedto quantify microvessel density (MVD). SPSS17.0was used for statistical analysis andp <0.05was considered statistically significant.Results: It was found that VIM expression was positive in the stroma of normalsalivary glands and in cribriform, tubular and solid patterns of salivary gland AdCC. Nosignificant difference of VIM expression was found between normal salivary glands and salivary gland AdCC (p>0.05). In addition, variation myoepithelial cells in the tumortissue can also be seen VIM positive expression. Expression of α-SMA was negative inthe stromal cells but positive in the myoepithelial cells and smooth muscle cells aroundthe small blood vessels in normal salivary glands. Positive stromal cells for α-SMAwere observed in cribriform, tubular and solid patterns of salivary gland AdCC. Theexpression level of α-SMA was significantly higher in salivary gland AdCC than that insalivary glands (p <0.001). In addition, variation myoepithelial cells in the tumor tissuecan also be seen α-SMA positive expression. CD34-positive endothelial cells liningmicrovessels were found in normal salivary glands and cribriform, tubular and solidpatterns of salivary gland AdCC. And the number of microvessels is much higher thanthat in normal salivary glands. Statistical analysis proved that the MVD value insalivary gland AdCC is higher than that in normal salivary glands significantly (p <0.001), suggesting the active angiogenesis in salivary gland AdCC. Although α-SMAexpression is stronger in salivary gland AdCC samples with increased MVD, nosignificant correlation was found between α-SMA expression and MVD in salivarygland AdCC (p>0.05).Conclusions: MVD in salivary gland AdCC is significantly higher than that innormal salivary glands. No significant relationship was found between MVD and CAFsin salivary gland AdCC.