Expression of lumican in thickened intima and smooth muscle cells in human coronary atherosclerosis

Lumican is a member of a small leucine-rich proteoglycan family. Members of this family play an important role in cell migration and proliferation during embryonic development, tissue repair, and tumor growth. Lumican is reported to be overexpressed during the wound-healing process in the cornea and ischemic and reperfused heart. Recently, we found that lumican mRNA and its protein are expressed in cultured vascular smooth muscle cells (VSMCs) from the rat aorta. However, the expression and role of lumican in human atherosclerotic tissues are not clearly elucidated. In the present study, we aimed to clarify whether lumican is expressed in VSMCs and its localization in human coronary atherosclerotic tissues. The lumican protein and its mRNA were expressed in a small number of VSMCs in the media of normal coronary artery, but the lumican protein was not localized in the medial stroma. In contrast, the lumican protein and its mRNA were expressed in most of VSMCs that migrated into the thickened intima, but not in infiltrating foamy macrophages. The lumican protein was prominently localized in the thickened intimal stroma. The lumican protein and its mRNA were also expressed in VSMCs in the inner layer of the media and its protein was localized in medial stromal tissues. These findings indicate that the lumican protein is mainly synthesized by intimal and medial VSMCs in coronary atherosclerosis and that lumican contributes to collagen fibrillogenesis of coronary atherosclerosis.     

Differential distribution of fibroblast growth factor (FGF)-7 and FGF-10 in L-arginine-induced acute pancreatitis

The regenerative process of the pancreas after acute pancreatitis (AP) is characterized by acinar and ductal cell proliferation with synthesis and transient deposition of extracellular matrices. Various growth factors were reported to be highly expressed in AP, but their regulation has not yet been clarified. Fibroblast growth factor (FGF)-7, also known as keratinocyte growth factor (KGF), and FGF-10 are members of the FGF family and show high structural homology and similar biological characteristics. Both are mainly synthesized by mesenchymal cells and stimulate epithelial cells via KGF receptor (KGFR) which is a splice variant of FGFR-2. In the present study, we attempted to immunohistochemically determine the localization of FGF-7 and FGF-10 in pancreatic tissues of an L-arginine-induced rat pancreatitis model. Furthermore, highly specific KGFR antibodies were prepared and used for Western blot analysis and immunohistochemistry. In the normal pancreas, FGF-7 was localized in alpha cells of islets, but FGF-10 was not detected. KGFR was also localized in islet cells, ductal cells, and centroacinar cells in the normal pancreas. In the pancreatic tissues of rats with L-arginine-induced pancreatitis, FGF-7 was localized in alpha cells, whereas FGF-10 was expressed in vascular smooth muscle cells (VSMCs). KGFR was not expressed in centroacinar cells and its level decreased after L-arginine treatment. However, KGFR was detected instead in some acinar cells and VSMCs in addition to islet cells. These findings suggest that FGF-7 and FGF-10 contribute to the regeneration and differentiation of acinar cells and angiogenesis in AP through KGFR.     

In chronic pancreatitis,widespread emergence of TRAIL receptors in epithelia coincides with neoexpression of TRAIL by pancreatic stellate cells of early fibrotic areas

TRAIL (TNF-related apoptosis-inducing ligand) induces apoptosis by cross-linking of the two TRAIL receptors that contain a death domain, TRAIL-R1 and TRAIL-R2. TRAIL-R3 and TRAIL-R4 are receptors that do not transmit an apoptotic signal. Our aim was to determine the expression of TRAIL and its receptors in normal pancreas and chronic pancreatitis. We applied real-time PCR, immunohisto(cyto)chemistry, and nick-end labeling of apoptosis. In normal pancreas, a minor subset of acinar cells coexpressed TRAIL-R2 and TRAIL-R4, whereas ductular epithelium and interstitial fibroblast-like cells (FLC) expressed TRAIL-R4. TRAIL-R1 and TRAIL-R3 were not detected in normal pancreas. In chronic pancreatitis, the exocrine epithelium strongly expressed TRAIL-R1, -R2, -R4, and, to a lesser extent, TRAIL-R3. Islets focally neoexpressed TRAIL-R1 and -R2 and intensely expressed TRAIL-R4. Changes in TRAIL receptor expression were most pronounced in areas of inflammatory infiltration and active fibrosis. In normal pancreas, expression of TRAIL was low on the mRNA level and undetectable on the protein level. In chronic pancreatitis, FLC in areas of active fibrosis expressed TRAIL. In addition, apoptosis were most numerous in these areas. We show that these FLC are pancreatic stellate cells. Pancreatic stellate cells express TRAIL in vivo and in vitro, and TRAIL expression is enhanced by IFN-gamma. Our findings indicate that the TRAIL/TRAIL receptor system is likely to be involved in chronic pancreatitis and suggest that pancreatic stellate cells may directly contribute to acinar regression by inducing apoptosis of parenchymal cells in a TRAIL-dependent manner.     

EXPRESSION OF ENDOTHELIN-1 IN PANCREATIC TISSUE OF PATIENTS WITH CHRONIC PANCREATITIS

Chronic pancreatitis is characterized by the presence of an inflammatory infiltrate, progressive destruction of acinar cells, and fibrosis. The finding that endothelin-1, an endothelium-derived peptide with vasoconstrictive and mitogenic properties, reduces pancreatic blood flow in normal rats suggested that the peptide may be associated with the reduced pancreatic flow seen in animal models of chronic pancreatitis and in the morphological abnormalities of the disease. The aim of this study was to investigate sites of endothelin-1 expression in the pancreas of normal subjects and patients with chronic pancreatitis. The techniques of immunohistochemistry, in situ hybridization, and Northern blotting were used. Endothelin-1-like immunoreactivity was localized predominantly to islet cells both in normal subjects and in patients with chronic pancreatitis. Semi-quantitative analyses of immunostaining showed that endothelin-1-like immunoreactivity in islet cells of patients with chronic pancreatitis was greater than in normal subjects. Co-localization studies with glucagon, insulin, somatostatin, and pancreatic polypeptide showed that endothelin-1-like immunoreactivity co-exists with glucagon and insulin. There was no apparent co-existence of endothelin-1-like immunoreactivity with somatostatin or pancreatic polypeptide. Endothelin-1 mRNA was expressed in sites similar to those of the immunostaining, as well as in vascular endothelial cells. Northern blot analysis showed an increase in the expression of endothelin-1 mRNA in the patient population. There was a significant correlation between intensity of endothelin-1 immunostaining and severity of fibrosis in the patients with chronic pancreatitis. These findings suggest that an elevation in local expression of endothelin-1 may be associated with the morphological and haemodynamic changes of chronic pancreatitis.     

Fibrosis of the pancreas: the initial tissue damage and the resulting pattern

Fibrosis in the pancreas is caused by such processes as necrosis/apoptosis, inflammation or duct obstruction. The initial event that induces fibrogenesis in the pancreas is an injury that may involve the interstitial mesenchymal cells, the duct cells and/or the acinar cells. Damage to any one of these tissue compartments of the pancreas is associated with cytokine-triggered transformation of resident fibroblasts/pancreatic stellate cells into myofibroblasts and the subsequent production and deposition of extracellular matrix. Depending on the site of injury in the pancreas and the involved tissue compartment, predominantly inter(peri)lobular fibrosis (as in alcoholic chronic pancreatitis), periductal fibrosis (as in hereditary pancreatitis), periductal and interlobular fibrosis (as in autoimmune pancreatitis) or diffuse inter- and intralobular fibrosis (as in obstructive chronic pancreatitis) develops.     

Lumican and decorin are differentially expressed in human breast carcinoma

Previous studies have shown that lumican is expressed and increased in the stroma of breast tumours. Lumican expression has now been examined relative to other members of the small leucine-rich proteoglycan gene family in normal and neoplastic breast tissues, to begin to determine its role in breast tumour progression. Western blot study showed that lumican protein is highly abundant relative to decorin, while biglycan and fibromodulin are only detected occasionally in breast tissues (n=15 cases). Further analysis of lumican and decorin expression performed in matched normal and tumour tissues by in situ hybridization showed that both mRNAs were expressed by similar fibroblast-like cells adjacent to epithelium. However, lumican mRNA expression was significantly increased in tumours (n=34, p<0.0001), while decorin mRNA was decreased (p=0.0002) in neoplastic relative to adjacent normal stroma. This was accompanied by a significant increase in lumican protein (n=12, p=0.0122), but not decorin. Further evidence of altered lumican expression in breast cancer was manifested by discordance between lumican mRNA and protein localization in some regions of tumours but not in adjacent morphologically normal tissues. It is concluded that lumican is the most abundant of these proteoglycans in breast tumours and that lumican and decorin are inversely regulated in association with breast tumourigenesis.     

Effect of morpholino antisense oligonucleotide against lumican mRNA in human embryonic kidney (HEK) 293 cells

Lumican is a member of the small-leucine-rich proteoglycan (SLRP) family and is overexpressed during wound healing of the cornea, in ischemic and reperfused heart, and in several cancer tissues. Lumican is considered to regulate the collagen fibril diameter and interfibrillar spacing. However, the effect of lumican on cell growth has not been adequately examined. In the present study, we attempted to clarify whether lumican contributes to human embryonic kidney (HEK) 293 cell growth, using the morpholino antisense oligonucleotide (m-anti oligo) against lumican mRNA. M-anti oligo is a novel oligonucleotide and exhibits a higher antisense activity, higher water solubility, and greater resistance to nucleases in target cells than phosphorothioate types of oligonucleotide. After delivery of m-anti oligo against lumican mRNA, the fluorescein 5-isothiocyanate (FITC) conjugated oligonucleotides were observed in the cytoplasm and nucleus of HEK 293 cells at 24 h by confocal laser microscopy. M-anti oligo for lumican mRNA strongly inhibited the synthesis of lumican protein in the HEK 293 cells, and the HEK cell growth rate was higher than those in the control groups. These findings may indicate that lumican protein has an inhibitory effect on HEK 293 cell growth in vitro .     

N-乙酰半胱氨酸对急性胰腺炎模型大鼠的保护作用

背景：急性胰腺炎是由胰腺腺泡细胞损伤介导的常见炎性疾病,白细胞浸润是其主要的发病特征。近来发现N-乙酰半胱氨酸能够控制白细胞游走并在一些严重的炎症疾病中发挥调节炎症反应的作用。 目的：观察N-乙酰半胱氨酸在体内对牛黄胆酸盐诱导的急性胰腺炎大鼠模型的保护作用。 方法：90只SD大鼠随机等分为正常对照组、急性胰腺炎组和N-乙酰半胱氨酸组,后2组以十二指肠大乳头逆行注射牛黄胆酸盐制备急性大鼠胰腺炎模型。N-乙酰半胱氨酸组大鼠由尾静脉给予N-乙酰半胱氨酸治疗。 结果与结论：急性胰腺炎模型诱导后大鼠血浆淀粉酶活性较正常对照组大鼠显著升高(P < 0.05)。急性胰腺炎组白细胞介素1β,6,10和肿瘤坏死因子α表达水平明显高于正常对照组(P < 0.05)。免疫荧光化学显示N-乙酰半胱氨酸主要表达在胰岛细胞上,急性胰腺炎组织N-乙酰半胱氨酸的表达从mRNA水平到蛋白水平都明显低于正常组织。N-乙酰半胱氨酸治疗显著降低了大鼠血清淀粉酶水平,髓过氧化物酶活性以及促炎性细胞因子产物生产和胰腺及肺组织损伤,但N-乙酰半胱氨酸治疗并没有明显抑制胰腺组织核因子κB的激活。提示N-乙酰半胱氨酸能改善急性胰腺炎大鼠胰腺和肺脏的组织损伤,并发挥抗炎症的作用。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程全文链接：     

Enhanced expression of lumican inhibited the attachment and growth of human embryonic kidney 293 cells

Lumican is a member of a small leucine-rich proteoglycan (SLRP) family and it regulates the assembly and diameter of collagen fibers in the extracellular matrix of various tissues. Lumican expression was reported in various kinds of tumor cells. Lumican inhibits the growth of melanoma cells, but the lumican in pancreatic cancer correlated with an advanced stage and retroperitoneal and duodenal invasion. In this study, we clarified whether the enhanced expression of lumican contributes to cellular attachment, growth, colony formation, migration and invasion. HEK 293 cell, stably transfected with lumican cDNA synthesized and secreted a 50 kDa lumican protein at high levels in culture medium. The cells showed a polygonal appearance with long projections and the degree of adhesion of the cells to fibronectin was lower than that of empty vector transfected control cells (mock cells). In contrast, the degree of adhesion of the cells to type I collagen was not different from that of mock cells. The expression levels of α5 integrin, the major integrin subunit for fibronectin, were lower in lumican-transfected HEK cells than in mock cells. Furthermore, lumican-transfected HEK cells showed reduced growth rates in vitro and did not form colonies in soft agar. Phosphorylation of AKT, extracellular signal-regulated kinase (ERK) 1/2 and mammalian target of rapamycin (mTOR) decreased in the lumican-transfected HEK cells. Cell migration and invasion were not altered in lumican-transfected HEK cells and mock cells. These findings indicate that the 50 kDa lumican protein plays important roles in the inhibition of HEK cell attachment and growth, and it might inhibit the activation of integrin pathways.     

脂蛋白脂酶基因缺陷的极度高甘油三酯血症小鼠胰腺炎的研

目的:利用一种特殊的脂蛋白脂酶（LPL）基因缺陷的极度高甘油三酯血症(HTG)小鼠，作为HTG性胰腺炎的实验动物模型，研究其胰腺炎发病特点。 方法:检测野生型及LPL缺陷的遗传性极度HTG小鼠血浆淀粉酶活性并观察胰腺的形态学改变，研究自发性胰腺炎的发生情况；通过腹腔注射左旋精氨酸（L-Arg）诱导小鼠发生急性胰腺炎（AP），研究HTG时胰腺炎易感性的变化。 结果:对胰腺组织的病理观察表明，LPL缺陷小鼠中约34.5%可发生自发性胰腺炎，特点主要为炎细胞浸润和腺泡破坏，有时伴纤维化和出血，病变严重程度与血浆TG水平呈正相关（r=0.604,P<0.05），血浆淀粉酶活性与对照组相比无明显差异。L-Arg诱导的LPL缺陷实验组小鼠胰腺炎病理损害明显重于野生型实验组（P<0.01），但两组间血浆淀粉酶活性无显著差异。 结论:LPL缺陷的HTG小鼠可发生自发性胰腺炎，对于L-Arg诱导的AP比野生型小鼠更加易感，为进一步研究HTG性胰腺炎的发病机制提供了理想的动物模型。     

Characterization of c-Kit and nestin expression during islet cell development in the prenatal and postnatal rat pancreas.

It has been well documented that there are abundant endocrine progenitor cells in the neonatal pancreas. However, little is known of their relative proportions or even their phenotypes. The aim of this study was to examine the normal distribution and characteristics of putative endocrine precursor cells, identified by c-Kit or nestin expression, within the prenatal and postnatal rat pancreas during islet cell development. Here, we provide evidence of the existence of a subset of ductal, islet, and acinar cells with an immature morphology and high proliferative capacity that expressed c-Kit or nestin. The proportion of islet cells expressing c-Kit or nestin was highest at embryonic day 18 (25 +/- 4% and 28 +/- 6%) and decreased significantly by postnatal day 28 (P < 0.01), 1.3 +/- 0.2% and 5.7 +/- 1%, respectively. The expression of nestin mRNA decreased throughout development, while c-Kit mRNA expression was found to slightly increase in the developing pancreas. Coexpression patterns indicated that c-Kit and nestin form two distinct cell populations in the postnatal pancreas, and infrequently coexpress with other pancreatic cell-specific markers. Furthermore, decreased c-Kit and nestin expression in the islets in postnatal life correlated with an increase in cells immunopositive for Pdx-1 compared with birth (36 +/- 5% vs. 60 +/- 3%, P < 0.01), which accompanied a doubling in the proportion of Glut-2-positive cells (39.4 +/- 4% vs. 68.8 +/- 3%, P < 0.01), both of which are mature beta-cell markers. Taken together, these findings suggest that c-Kit- and nestin-expressing cells represent endocrine precursor cells that undergo marked changes in population dynamics during the transition from prenatal to postnatal pancreatic development in the rat. Characterization of the phenotype, relative abundance and location of these cells within the developing pancreas is an important step toward creating a strategy for isolating stem cell populations and modeling islet cell differentiation in vitro.     

Redox-sensitive modulation of CD45 expression in pancreatic acinar cells during acute pancreatitis

CD45, a transmembrane protein tyrosine phosphatase required for signal transduction in leukocytes, has recently been found in pancreatic acinar cells. We have investigated the relationship between kinetic expression of CD45 on acinar cells during acute pancreatitis (AP) and the ability of these cells to produce tumour necrosis factor-alpha (TNF-alpha) through mechanisms sensitive to the cellular redox state. Flow cytometric analysis showed a significant decrease in the constitutive expression of CD45 in acinar cells from six hours onwards after inducing AP by bile-pancreatic duct obstruction (BPDO) in parallel with a significant increase in acinar TNF-alpha production. Changes in protein expression on the acinar cell surface preceded CD45 mRNA down-regulation, which was not found until 12 hours after BPDO. N-Acetylcysteine treatment delayed and reduced the down-regulation of CD45 expression induced by AP and prevented acinar cells from producing TNF-alpha. Our results show that CD45 expression is down-regulated in acinar cells during acute pancreatitis by redox-sensitive mechanisms, and they support the notion that CD45 negatively controls the production of cytokines in pancreatic acinar cells.     

Fas/FasL介导的caspase-3活化与急性胰腺炎腺泡细胞凋亡的关系

目的： 研究凋亡调控基因及蛋白Fas、FasL和caspase-3在大鼠急性胰腺炎（AP）组织中的表达及其相互关系。方法：经胰胆管逆行注射不同浓度的牛磺胆酸钠建立不同炎症程度的AP模型,采用RT-PCR、Western blotting技术检测大鼠胰腺炎组织Fas、FasL和caspase-3蛋白及mRNA的表达, TUNEL法检测胰腺炎组织腺泡细胞凋亡。结果：在正常胰腺组织内即可见Fas、FasL、caspase-3蛋白和mRNA的表达;建立AP模型后,随胰腺炎症程度的加重,Fas、FasL、caspase-3蛋白和mRNA的表达逐渐下降,腺泡细胞凋亡率亦逐渐下降,且caspase-3 表达水平在各个组间的变化趋势与Fas/FasL系统的变化趋势相一致。结论：Fas/FasL系统介导的凋亡途径参与了急性胰腺炎腺泡细胞凋亡的调节。     

性别对L-精氨酸诱发的昆明小鼠慢性胰腺炎的影响

目的:通过比较雌雄小鼠L-精氨酸诱发的慢性胰腺炎(CP)程度的差异,探讨性别对CP模型形成的影响。方法:健康昆明小鼠雌雄各42只,分为雌性对照组、雌性CP组、雄性对照组和雄性CP组(对照组n=18,每时点6只;CP组n=24,每时点8只)。CP模型组小鼠腹腔注射20%L-精氨酸(3 g/kg,每周1次,每次2轮,间隔1 h)诱发CP。分别于造模后第2、4、6周处死动物,取小鼠胰腺组织,HE及Masson染色检测各组小鼠胰腺形态学改变及纤维化程度;免疫组织化学观察胰腺组织F4/80的阳性染色率;real-time PCR检测胰腺组织白细胞介素6(interleukin-6,IL-6)、α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)及纤维连接蛋白(fibronectin,FN)的mRNA表达;Western blot检测胰腺组织α-SMA及FN蛋白的表达。结果:20%L-精氨酸腹腔注射后的第2、4和6周,HE及Masson染色显示雌雄CP组胰腺组织均可见病理损伤,但是同一时点雌雄小鼠胰腺损伤程度存在明显差异,雄性小鼠胰腺病变程度明显较重;胰腺F4/80染色显示雄性小鼠胰腺F4/80的表达水平在造模后各时点均明显高于同一时点的雌性小鼠;造模后第2和4周胰腺IL-6的mRNA表达在雌雄CP组均有所升高,但是雄性组表达水平明显高于雌性组(P0.05)。造模后α-SMA和FN在mRNA水平和蛋白质水平均可见高表达,但雄性小鼠表达时点更早,水平更高(P0.05)。结论:采用腹腔注射20%L-精氨酸可成功复制小鼠CP模型,但复制的模型在雌雄小鼠存在病变程度差异。L-精氨酸诱导的CP模型在雄性小鼠成模更早、纤维化程度更明显,其原因可能与雄性小鼠对L-精氨酸更敏感,引发的炎症反应程度更明显有关。雄性小鼠更适合于复制CP动物模型。     

Cellular localization of transforming growth factor-beta expression in bleomycin-induced pulmonary fibrosis.

Bleomycin-induced pulmonary fibrosis is associated with increased lung transforming growth factor-beta (TGF-beta) gene expression, but cellular localization of the source of this expression has not been unequivocally established. In this study, lung fibrosis was induced in rats by endotracheal bleomycin injection on day 0 and, on selected days afterwards, lungs were harvested for in situ hybridization, immunohistochemical and histochemical analyses for TGF-beta 1 mRNA and protein expression, and cell identification. The results show that control lungs express essentially no detectable TGF-beta 1 mRNA or protein in the parenchyma. Before day 3 after bleomycin treatment, scattered bronchiolar epithelial cells, mononuclear cells, and eosinophils expressed elevated levels of TGF-beta 1. Between days 3 and 14, there was a major increase in the number of eosinophils, myofibroblasts, and fibroblasts strongly expressing TGF-beta 1 mRNA and protein. TGF-beta 1-producing cells were predominantly localized within areas of injury and active fibrosis. After day 14, the intensity and number of TGF-beta 1-expressing cells significantly declined and were predominantly found in fibroblasts in fibrotic areas. The expression of TGF-beta 1 protein was generally coincident with that for mRNA with the exception of bronchiolar epithelial cells in which strong protein expression was unaccompanied by a commensurate increase in mRNA. The study demonstrates that myofibroblasts, fibroblasts, and eosinophils represent the major sources of increased lung TGF-beta 1 expression in this model of pulmonary fibrosis.     

The physiology of a local renin–angiotensin system in the pancreas

The systemic renin–angiotensin system (RAS) plays an important role in regulating blood pressure, electrolyte and fluid homeostasis. However, local RASs also exist in diverse tissues and organs, where they play a multitude of autocrine, paracrine and intracrine physiological roles. The existence of a local RAS is now recognized in pancreatic acinar, islet, duct, endothelial and stellate cells, the expression of which is modulated in response to physiological and pathophysiological stimuli such as hypoxia, pancreatitis, islet transplantation, hyperglycaemia, and diabetes mellitus. This pancreatic RAS has been proposed to have important endocrine and exocrine roles in the pancreas, regulating local blood flow, duct cell sodium bicarbonate secretion, acinar cell digestive enzyme secretion, islet beta-cell (pro)insulin biosynthesis, and thus, glucose-stimulated insulin release, delta-cell somatostatin secretion, and pancreatic cell proliferation and differentiation. It may further mediate oxidative stress-induced cell inflammation, apoptosis and fibrosis. Further exploration of this system would probably offer new insights into the pathogenesis of pancreatitis, diabetes, cystic fibrosis and pancreatic cancer formation. New therapeutic targets and strategies might thus be suggested.     

Lumican expression is associated with the formation of mesenchyme-like elements in salivary pleomorphic adenomas

Pleomorphic adenomas are the most common salivary gland tumour. Although this tumour is considered to be of epithelial origin, it contains 'mesenchyme'-like elements histologically. Lumican is a keratan sulphate proteoglycan that belongs to the small leucine-rich repeat (LRR) proteoglycans and has been reported to be associated with cartilage formation. These findings suggest that lumican expression may be related to the chondroid component in pleomorphic adenomas. To investigate this hypothesis, the present study investigated the expression and localization of lumican in 20 normal human salivary glands and 35 pleomorphic adenomas. Firstly, immunohistochemistry for lumican was performed with pepsin pretreatment. In normal salivary glands, lumican was deposited in the periductal regions. In pleomorphic adenomas, it was predominantly deposited in the hyaline (100%) and fibrous areas (89.4%). In 16 tumours (66.7%), lumican was also deposited in the chondroid areas. Without pepsin pretreatment, lumican was identified in myoepithelial cells in myxoid areas, lacuna cells in chondroid areas, and in the cytoplasm of inner ductal cells. In situ hybridization revealed lumican mRNA expression mainly in the inner cells, the neoplastic myoepithelial cells, and the lacuna cells. These results suggest that lumican is associated with the formation of 'mesenchyme'-like structures in pleomorphic adenomas. In conclusion, normal salivary glands express lumican, which appears to be related to stromal maintenance, and pleomorphic adenomas express lumican mRNA and protein, which may play important roles in the formation of 'mesenchyme'-like areas in this type of tumour.