Lymphatic vessels and related factors in adenoid cystic carcinoma of the salivary gland

Analyses of VEGFC/VEGF-D expressions, density and endothelial lymphatic proliferation in salivary gland neoplasms

OBJECTIVE

The aim of this study was to assess vascular endothelial growth factor C (VEGF-C) and VEGF-D expressions, tumor lymphatic density (D2-40) and endothelial lymphatic proliferation (D2-40/Ki-67 double labeling) in a series of salivary gland neoplasm cases.

MATERIALS AND METHODS

Twenty pleomorphic adenomas (PA), 20 adenoid cystic carcinomas (ACC) and 20 mucoepidermoid carcinomas (MEC) were assessed, as well as 10 normal minor salivary gland (SG) tissues for comparison.

RESULTS

All cases presented positive VEGF-C expression in the peritumoral and intratumoral regions, and no differences in immunoexpression were detected between groups. However, the ACC group presented a significant difference in VEGF-C immunoexpression according to the predominant histological pattern. Most cases presented poor VEGF-D labeling in the peritumoral and intratumoral regions. Concerning peritumoral, intratumoral and total lymphatic endothelial density, the assessed groups revealed an increasing gradient, with lower values for PA, followed by MEC and ACC.

CONCLUSION

No correlation was detected between VEGF-C and VEGF-D immunoexpression in relation to lymphatic tumor density and endothelial lymphatic proliferation. Western blotting (WB) revealed no difference between VEGF-C and VEGF-D expression among the lesions, corroborating the immunohistochemistry findings.

Angiogenesis and Lymphangiogenesis in Salivary Gland Adenoid Cystic Carcinoma and Mucoepidermoid Carcinoma

BACKGROUND AND PURPOSE

This study aimed to investigate the immunohistochemical expression of CD31 and podoplanin in order to examine angiogenesis and lymphangiogenesis, respectively in common malignant tumors of salivary glands.

MATERIALS AND METHODS

Forty formalin-fixed, paraffinated blocks (20 adenoid cystic carcinoma and 20 mucoepidermoid carcinoma blocks) were selected from the medical archives of Amir A'lam Hospital of Tehran, Iran. Sections from the blocks were stained by CD31 and D2-40 markers via immunohistochemistry. Clinical and demographic information was extracted from the patients' records.

FINDINGS

There was a significant difference between tumors in terms of intratumoral microvessel density (MVD) (P< 0.001), total MVD (P< 0.001), and intratumoral lymphatic vessel density (LVD) (P= 0.011). In mucoepidermoid carcinoma, intratumoral MVD and LVD were greater than peritumoral MVD and LVD (P= 0.001 and P< 0.001, respectively). In mucoepidermoid carcinoma, there was no relationship between histological grade with MVD (total, intratumoral or peritumoral) or LVD (total, intratumoral or peritumoral) (P> 0.05). A similar finding was reported with respect to the histopathological grade of adenoid cystic carcinoma (P> 0.05).

CONCLUSION

The higher level of angiogenesis and lymphangiogenesis in mucoepidermoid carcinoma, specifically at the center of tumor, compared to adenoid cystic carcinoma, may be attributed to differences in the clinical behaviors and metastasis of tumors. Moreover, considering the high LVD at the center of tumor in mucoepidermoid carcinoma and infrequency of metastasis to regional lymph nodes in adenoid cystic carcinoma, it can play a significant role in metastasis to regional lymph nodes.

Clinical implications of aberrant neurovascular structures coursing through the submandibular gland

Background

Variation within the submandibular triangle, including variant paths of facial neurovasculature, could increase risk of neurovascular derangement during submandibular gland (SMG) dysfunction, enlargement, interventions, or removal.

Methods

Frequency of anatomical variants enveloped within or piercing the SMG, including facial artery, vein, or branches of CN VII, were assessed in 70 cadaveric submandibular glands (39M/31F).

Results

Eighteen of 70 SMGs (25.7%) were pierced by at least one aberrant neurovasculature structure: Facial artery most frequently (n = 13), followed by facial vein (n = 2), inferior labial artery and vein (n = 1), and CN VII cervical branch (n = 1). This study demonstrated the high variability of neurovasculature within submandibular parenchyma. These aberrant neurovascular structures, especially facial artery, are in danger of compromise during surgical and other medical procedures on the SMG. To avoid potential neurovascular compromise, ultrasonographic or other imaging is recommended prior to procedures involving the SMG.

Role of apoptotic, autophagic and senescence pathways in minor salivary gland adenoid cystic carcinoma

Background

Adenoid cystic carcinoma (ACC) is a salivary gland malignancy with poor long-term survival, which warrants studies aimed at clarifying the pathogenesis of this disease in order to widen the scope of therapeutic options currently available. Alterations in regulatory mechanisms relating to vascular support, cell death and autophagy are important pathways for tumor growth in cancer. Thus, the present study aimed to access vascular supply, apoptosis, autophagy and cell senescence in ACC of minor salivary glands.

Methods

We analyzed 25 cases of minor salivary gland ACC by immunohistochemistry using anti-CD34, anti-CD105, anti-D2–40, anti-Bax, anti-Bcl-2, anti-Beclin-1, anti-LC3B, anti-p21 and anti-p16.

Results

Microvessel density was low and based on anti-CD34, anti-CD105 and anti-D2–40 immunostaining. There was positivity for anti-CD34, anti-Bcl-2, anti-Beclin, anti-LC3B and anti-p21 and a positive correlation between Bcl-2 and Beclin (p = 0.014).

Conclusions

Our results showed that ACC does not depend on neo-angiogenesis and is probably associated to anti-apoptotic, autophagic and anti-senescence events.

Daily voluntary exercise enhances pilocarpine-induced saliva secretion and aquaporin 1 expression in rat submandibular glands

Saliva—a water‐based fluid containing electrolytes, immunoglobulins, and enzymes—has many functions, including the protection and hydration of mucosal structures within the oral cavity and the initiation of digestion. Aquaporins (AQPs) are proteins that act as water channels through membranes. We have previously reported upregulation of the expression levels of AQP 1 and 5 in the submandibular glands (SMGs) in heat‐acclimated rats. In this study, we investigated pilocarpine‐induced saliva secretion and AQP expression in rats after voluntary exercise. Male, 10‐week‐old Wistar rats were initially maintained at an ambient temperature of 24 °C for 10 days and were then kept for 40 days in cages either with a running wheel (exercise rats, n = 6) or with a locked wheel [control rats (CN), n = 6]. After the training period, the rats were anesthetized and pilocarpine, an M3 muscarinic receptor agonist, was intraperitoneally injected (0.5 mg·kg⁻¹) to stimulate saliva secretion. Saliva was collected, and the SMGs were sampled and subjected to western blot, RT‐PCR, and immunohistochemical analyses. Pilocarpine induced a greater amount of saliva in the exercised rats than in the CN. Expression levels of AQP1 mRNA and protein were significantly higher in SMGs of exercised rats than in those of the CN, but the expression of AQP5 was not affected by voluntary exercise. Voluntary exercise increased the expression of vascular endothelial growth factor (VEGF) and cluster of differentiation 31 (CD31), a marker for endothelial cells, in the SMGs. Voluntary exercise promoted pilocarpine‐induced saliva secretion, probably via an increase in the expression level of AQP1 due to VEGF‐induced CD31‐positive angiogenesis in the SMG.

Adenoid cystic carcinoma of the minor salivary glands: a retrospective series of 29 cases and review of the literature

OBJECTIVE

Approximately 78% of minor salivary gland tumors are malignant, of which adenoid cystic carcinoma (ACC) represents 15% in our series. ACC is an uncommon tumor characterized by slow growth and a high potential for recurrence. This series of 29 consecutive patients examines clincopathologic features, management, and survival outcomes.

MATERIALS AND METHODS

This study is a retrospective chart review of 29 patients with ACC of the minor salivary glands in a period of 23 years (1989 and 2012).

RESULTS

The mean age was 61.2 years (16-89 years), with no gender predilection. The majority occurred in the palate/maxilla (66%) and initial presentation was stage IV. Mean follow-up was 42.6 months. Recurrence rate was 10% local, 14% distant over the observation period.

CONCLUSIONS

The palate/maxilla is the preferred location for occurrence, and initial presentation at stage IV is common. Postoperative radiation remains a common strategy to prevent local recurrence in lesions with adverse features.

Adenoid cystic carcinoma of the head and neck--An update

This article provides an update on the current understanding of adenoid cystic carcinoma of the head and neck, including a review of its epidemiology, clinical behavior, pathology, molecular biology, diagnostic workup, treatment and prognosis. Adenoid cystic carcinoma is an uncommon salivary gland tumor that may arise in a wide variety of anatomical sites in the head and neck, often with an advanced stage at diagnosis. The clinical course is characterized by very late recurrences; consequently, clinical follow-up should extend at least >15 years. The optimal treatment is generally considered to be surgery with postoperative radiotherapy to optimize local disease control. Much effort has been invested into understanding the tumor's molecular biological processes, aiming to identify patients at high risk of recurrence, in hopes that they could benefit from other, still unproven treatment modalities such as chemotherapy or biological therapy.

Neither expression of VEGF-C/D nor lymph vessel density supports lymphatic invasion as the mechanism responsible for local spread of recurrent salivary pleomorphic adenoma

Recent research suggests that multinodular recurrent pleomorphic adenoma (PA) might result from cell migration through lymphatics. Lymphangiogenesis in malignancies is mediated by vascular endothelial growth factors C and D (VEGF-C/D). We studied the expression of VEGF-C/D in PA by immunohistochemistry as well as lymphatic vessel density (LVD). In 6 non-recurrent, 4 primary-to-recur, and 10 recurrent PAs, VEGF-C/D expression was assessed by immunohistochemistry. Staining was scored in terms of staining intensity (0 = absent to 3 = strong), and the percentage of positive tumor cells (scored as 0 (0-19 %), 1 (20-39 %), 2 (40-50 %), and 3 (60-100 %)) and a sum score were calculated. Intra- and peritumoral LVD was assessed by counting of LV after immunostaining, using the D2-40 antibody. All but one sample were VEGF-C negative. The differences in VEGF-D expression between non-recurrent, primary-to-recur, and recurrent PAs were not significant (p>0.05). VEGF-D expression did not correlate with peritumoral LVD (p>0.05). Our study revealed a significant difference between intra- and peritumoral LVD values when comparing individual and all sample groups (p=0.01). The lack of VEGF-C expression and of significant differences in VEGF-D expression and peritumoral LVD between patients with non-recurrent, primary-to-recur, and recurrent PAs does not support the lymphangiogenic local spread hypothesis

Comparison of adenoid cystic carcinomas arising from the parotid gland vs. the submandibular gland: focus on systemic metastasis and tumor-associated blood vessels

BACKGROUND

Although several studies reported that distant metastasis occurs more frequently in the tumors of submandibular gland (SMG) than parotid gland (PG), why SMG tumors preferentially metastasize to distant organs is not fully understood. We aimed to identify the differential tumor microenvironment for distant metastasis and possible underlying mechanisms.

METHODS

We retrieved 27 cases of 1-4-cm-sized adenoid cystic carcinomas (ACCs) arising from the PG (n = 12) and SMG (n = 15). c-KIT, VEGF-R2, and CD31 staining were quantified by image-based analysis to define the positive expression or tumor-associated vessel areas in two representative sections per case. In addition, angiogenesis-related genomic expression profiling was carried out to explore the underlying mechanism, which was confirmed by RT-PCR and immunohistochemistry.

RESULTS

Earlier systemic dissemination within 2 years was detected exclusively in SMG ACCs (5/15). The area of tumor-associated blood vessels was larger in SMG ACCs than PG ACCs, and ACCs showing distant metastasis had greater blood vessel area than those without metastasis. Interestingly, normal SMG had more blood vessels per area than PG. Among angiogenesis-related signals, the level of IL-6 was significantly lower in SMG ACCs than PG ACCs. Moreover, IL-6 expression decreased significantly in SMG ACCs compared with that in normal SMG, whereas it was up-regulated in PG ACCs.

CONCLUSION

ACCs in the SMG microenvironment have more abundant tumor-associated blood vessels than PG ACCs, which may explain the higher risk of distant metastasis from SMG tumors.

Vascular endothelial growth factor (VEGF) expression and microvascular density in salivary gland tumours

This study investigates whether salivary tumours with different morphology and evolution also differ in terms of neovascularization and VEGF expression and the prognostic value of the results. Surgical specimens from 45 patients - 8 pleomorphic adenomas (PA), 7 Warthin tumours (WT), 5 basal cell adenomas (BA), 6 carcinomas ex-pleomorphic adenoma (CEPA), 6 mucoepidermoid carcinomas (MEC), 5 acinic cell carcinomas (AC), 4 adenoid cystic carcinomas (ACC) and 4 adenocarcinomas not otherwise specified (ADK NOS) - were immunostained. In malignant salivary tumours, the following mean microvascular density (MVD) values were recorded (± SD = Standard Deviation): 27.61 (SD ± 2.27) in cases with CEPA, 27.08 (DS ± 7.81) in AC and 32.93 (SD ± 7.76) in ADK NOS, with lower values for MEC 24.31(SD ± 2.88) and for ACC 22.13 (SD ± 5.44). For benign tumours, an MVD of 35.71 (SD ± 2.09) was recorded in WT and lower average values in PA (MVD = 14.84; SD ± 4.86) and in BA (MVD = 23.96; SD ± 9.13). MVD did not correlate with the investigated clinicopathological parameters. The VEGF expression is significantly more important (p = 0.001) in malignant salivary tumours as compared with benign ones. The VEGF expression and the microvascularization in salivary gland tumours are important elements to be considered when formulating a diagnosis and assessing case evolutions in patients with such tumours.

Expression of podoplanin in salivary gland adenoid cystic carcinoma and its association with distant metastasis and clinical outcomes

Distant metastasis is a common cause of mortality in patients with salivary gland adenoid cystic carcinoma (SACC). However, presently, the development of distant metastasis is unable to be predicted in clinical practice. Recent studies have shown that overexpression of podoplanin is associated with metastasis and survival in patients with several cancer types. The purpose of the present study was to determine whether podoplanin is overexpressed in SACC and whether such overexpression is associated with distant metastasis and survival. Podoplanin expression was determined using immunohistochemistry (IHC) in tumors from 40 SACC patients. The expression status was analyzed in regards to patient clinicopathological parameters and survival rates. Overexpression of podoplanin was detected in 13 (32.5%) of the 40 tumors. Overexpression was significantly associated with disease-free survival (P=0.025) and distant metastasis (P=0.015), although it was not associated with recurrence and overall survival. In conclusion, podoplanin is overexpressed in a subset of SACCs and may be a biomarker predicting distant metastasis in patients with SACC.