TGFβ signaling pathway in salivary gland tumors

OBJECTIVE

Pleomorphic adenoma (PA), mucoepidermoid carcinoma (MEC), and adenoid cystic carcinoma (ACC) are the most prevalent salivary gland tumors. Their pathogenesis has been recently associated with complex molecular cascades, including the TGFβ signaling pathway. The aim of this study was to evaluate the expression of genes associated with the TGFβ signaling pathway (TGFB1, ITGB6, SMAD2, SMAD4, FBN1, LTBP1, and c-MYC) to map possible downstream alterations in the TGFβ cascade.

DESIGN

Thirteen PA, 17 MEC, 13 ACC, and 10 non-neoplastic salivary gland samples were analyzed by real-time RT-PCR.

RESULTS

Cases of PA presented increased TGFB1, LTPB1, c-MYC, and FBN1 expressions, whereas SMAD2 expression was decreased when compared to non-neoplastic tissue. MEC patients displayed increased expressions of TGFB1, ITGB6, FBN1, and c-MYC and decreased expressions of SMAD2 and SMAD4. ACC cases exhibited elevated expressions of the investigated genes except TGFB1. The present results suggest that decreased expression of SMAD2 and SMAD4 does not impede the transcriptional regulation of c-MYC, especially in PA and MEC. Increased expressions of ITGB6, TGFB1, LTBP1, and FBN1 appear to be related to the regulation of the TGFβ signaling pathway in these tumors. Additionally, we observed a higher expression of SMAD4 in ACC and a raised expression of ITGB6 and lowered expression of SMAD2 in MEC.

CONCLUSIONS

Our study demonstrated the differential expression of TGFβ cascade members in salivary gland tumors such as SMAD2/SMAD4 and c-MYC as well as the participation of ITGB6, TGFB1, LTBP1, and FBN1, contributing to the understanding of the mechanisms involved in tumor progression.

Expression of Periostin in Benign Salivary Gland Tumors

Parotid tumors present a wide range of histological features, from benign to malignant. Periostin, an extracellular matrix protein specifically expressed in the periosteum and periodontal ligament, is isolated from osteoblast cell lines. It regulates fibrosis and collagen deposition and plays an important role in myocardial repair after myocardial infarction. It is also known to be involved in otorhinolaryngological-diseases. This study included 36 patients [38 specimens; 16 men and 20 women, mean age 59.2 (range 26-82) years] who underwent parotid tumor resection at the Division of Otorhinolaryngology, Tohoku Medical and Pharmaceutical University, between April 2017 and March 2022 and were clinically and pathologically diagnosed as having benign parotid tumors. Formalin-fixed, paraffin-embedded sections from the surgical specimens were autoclaved and immunostained with anti-periostin antibodies to evaluate the expression and distribution of periostin. Histologically, the tumors were diagnosed as pleomorphic adenomas in 15 cases (15 specimens), Warthin's tumors in 13 cases (15 specimens), basal cell adenomas in 2 cases (2 specimens), oncocytomas in 4 cases (4 specimens), and myoepitheliomas in 2 cases (2 specimens). An increased expression of periostin was found in 32 of 38 samples (84.2%) in the stroma of benign parotid tumors. Four distinct patterns of periostin expression were observed in benign parotid gland tumors: negative, superficial, infiltrative, and diffuse. Statistically significant differences were found between periostin expression patterns and histological classification of the tumors. Our results suggest that periostin may be involved in the pathogenesis of benign parotid tumors and could serve as a new biomarker for these tumors.

BubR1 and cyclin B1 immunoexpression in pleomorphic adenoma and polymorphous adenocarcinoma of minor salivary glands

The immunoexpression of BubR1 and cyclin B1 in pleomorphic adenoma (PA) and polymorphic adenocarcinoma (PAC) in minor salivary glands is poorly studied. Thus, a retrospective and observational study was performed to provide a better understanding of the role and immunopositivity patterns of these proteins in these lesions. Sixteen cases of PA and 16 cases of PAC were selected. Parenchyma cells were submitted to quantitative immunohistochemical analysis through the labeling index. Cytoplasmic immunoexpression of BubR1 was observed in neoplastic cells from all analyzed PA and PAC cases. All PA cases and 93.7% of PAC exhibited nuclear immunoexpression of BubR1. Higher cytoplasmic and nuclear immunoexpression of BubR1 was observed in PAC (p = 0.001 and p = 0.122, respectively). Cytoplasmic immunoexpression of cyclin B1 was observed in all cases of PA and PAC, with a higher labeling index in the latter (p < 0.001). There was a significant positive correlation between nuclear and cytoplasmic BubR1 immunoexpressions (p < 0.001) in PA and a significant negative correlation between BubR1 and cyclin B1 cytoplasmic immunoexpressions (p = 0.014) in PAC. The higher cytoplasmic and nuclear immunoexpression of BubR1 in PACs suggests the continuous maintenance of neoplastic cells in the cell cycle and migration. Higher immunoexpression of cyclin B1 supports this lesion's enhanced proliferative and migration ability.

Estrogen, Progesterone and Androgen Receptor in Primary and Recurrent Pleomorphic Salivary Adenomas

OBJECTIVE

Our study aimed to characterize alteration in the immunohistochemical expression of estrogen, progesterone and androgen receptor in the tumour cells of primary pleomorphic adenomas and recurrent pleomorphic adenomas.

METHODS

A retrospective study of data including 30 cases of primary pleomorphic adenomas (PA) without recurrences and 15 cases of recurrent pleomorphic adenomas were examined (RPA). RPA included 8 males and 7 females. Immunohistochemical expression of estrogen, progesterone and androgen receptor was examined in the selected cases. The percentage of slides was semi-quantitatively assessed by two independent observers and scores were given. The statistical analysis included the use of descriptive statistics and proportional frequencies.

RESULTS

AR expression was identified in 12 (40. %) out of 30 cases of (PA) pleomorphic adenomas and 7 of 15 cases recurrent pleomorphic adenomas (RPA) (46 %). The results showed that ER and PR expression were negative in PA and RPA.

CONCLUSION

Androgen receptors might have role in pathogenesis of PA and RPA. Estrogen and progesterone receptors have no role in development of recurrent pleomorphic salivary adenoma.

Effect of tumor-stromal fibroblasts on the biological behavior of salivary gland pleomorphic adenoma cells in vitro

OBJECTIVES

This study aims to investigate the effects of tumor-stromal fibroblasts (TSFs) on the proliferation, invasion, and migration of salivary gland pleomorphic adenoma (SPA) cells in vitro.

METHODS

Salivary gland pleomorphic adenoma cells (SPACs), TSFs, and peri-tumorous normal fibroblasts (NFs) were obtained by tissue primary culture and identified by immunocytochemical staining. The conditioned medium was obtained from TSF and NF in logarithmic phase. SPACs were cultured by conditioned medium and treated by TSF (group TSF-SPAC) and NF (group NF-SPAC). SPACs were used as the control group. The proliferation, invasion, and migration of the three groups of cells were detected by MTT, transwell, and scratch assays, respectively. The expression of vascular endothelial growth factor (VEGF) in the three groups was tested by enzyme linked immunosorbent assay (ELISA).

RESULTS

Immunocytochemical staining showed positive vimentin expression in NF and TSF. Results also indicated the weak positive expression of α-smooth muscle actin (SMA) and fibroblast activation protein (FAP) in TSFs and the negative expression of α-SMA and FAP in NFs. MTT assay showed that cell proliferation in the TSF-SPAC group was significantly different from that in the NF-SPAC and SPAC groups (P<0.05). Cell proliferation was not different between the NF-SPAC and SPAC groups (P>0.05). Transwell and scratch assays showed no difference in cell invasion and migration among the groups (P>0.05). ELISA showed that no significant difference in VEGF expression among the three groups (P>0.05).

CONCLUSIONS

TSFs may be involved in SPA biological behavior by promoting the proliferation of SPACs but has no effect on the invasion and migration of SPACs in vitro. Hence, TSF may be a new therapeutic target in SPA treatment.

Discovery proteomics reveals potential protein signature associated with malignant phenotype acquisition in pleomorphic adenoma

OBJECTIVE

To analyze the proteomic profile of salivary pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma (CXPA) samples and correlate them with the malignant transformation of the PA.

MATERIALS AND METHODS

Thirty samples (10 PA, 16 CXPA, and 4 residual PA) were microdissected and submitted to liquid chromatography-tandem mass spectrometry (LC-MS/MS). The proteomic data and protein identification were analyzed through LC-MS/MS spectra using the MaxQuant software.

RESULTS

The proteomic analysis identified and quantified a total of 240 proteins in which 135 were found in PA, residual PA, and CXPA. The shared proteins were divided into six subgroups, and the proteins that showed statistically significant differences (p > 0.05) and fold-change > or <2.5 in one subgroup to another subgroup were included. Seven proteins (Apolipoprotein A-I-APOA1, haptoglobin-HP, protein of the synaptonemal complex 1-SYCP1, anion transport protein of band 3-SLC4A1, subunit μ1 of AP-1 complex-AP1M1, beta subunit of hemoglobin-HBB, and dermcidin-DCD) were classified as potential protein signatures, being HP, AP1M1, and HBB with higher abundance for PA to residual PA, APOA1 with higher abundance for PA to CXPA, SLC4A1 with lower abundance in the PA to CXPA, SYCP1with lower abundance for residual PA to CXPA, and DCD with higher abundance in the CXPA with epithelial differentiation to myoepithelial differentiation.

CONCLUSIONS

In this work, we demonstrated the comparative proteomic profiling of PA, residual PA, and CXPA, and seven were proposed as protein signatures, some of which may be associated with the malignant phenotype acquisition.

CD24-gold nanocomposite as promising and sensitive biomarker for cancer stem cells in salivary gland tumors

Cancer stem cells are highly tumorigenic cells in the majority of the tumor that are responsible for the initiation, rapid growth, invasion, metastasis, and therapeutic resistance associated with various human cancers. The aim of this project is to assess a diagnostic and prognostic biomarker for the detection of cancer stem cells in salivary gland tumors using gold nanoparticles that are synthesized and conjugated to CD24 primer to form a CD24-Gold Nanocomposite. Sixty cases were included (29 pleomorphic adenoma, 19 carcinoma ex pleomorphic adenoma, and 12 normal controls). Alterations in biomarker expression between studied groups were analyzed and correlated with clinicopathological characteristics using Fisher's exact and Chi-square tests. ROC and Kaplan-Meier curves were used to validate diagnostic and prognostic values, respectively. This study confirms that CD24-Gold Nanocomposite served as a promising and highly sensitive biomarker in salivary gland tumor diagnosis and prognosis prediction.

Pleomorphic adenoma gene 1 (PLAG1) promotes proliferation and inhibits apoptosis of bovine primary myoblasts through the PI3K-Akt signaling pathway

Pleomorphic adenoma gene 1 (PLAG1) is a transcription factor involved in various cellular processes in organismal growth and development. However, its role in muscle function is unclear. This work investigated the roles of PLAG1 in muscle development and explored its regulatory mechanisms. The PLAG1 was proved to promote the proliferation of bovine primary myoblasts using the cell counting kit 8 (CCK-8) assay (P < 0.001), 5-ethynyl-2'-deoxyuridine (EdU) proliferation assay (P = 0.005), quantitative real-time polymerase chain reaction (qRT-PCR) (P = 0.028), western blot, and flow cytometry (P < 0.05), and to inhibit apoptosis of bovine primary myoblasts using qRT-PCR (P = 0.038), western blot, and flow cytometry (P < 0.001). Chromatin immunoprecipitation sequencing (ChIP-seq) and western blot showed PLAG1 upregulated phosphorylated (p)-PI3K, PI3K, p-Akt, Akt, Cyclin D1, and CDK2 and inhibited the expression of p21 and p27 to enhance myoblast proliferation, and increased expression of Bcl-2, and Bcl-xL to inhibit apoptosis. Additionally, PLAG1 was identified as a target of miR-1 using dual-luciferase assay (P < 0.001), qRT-PCR (P < 0.001), and western blot. Furthermore, miR-1 might be a potential mediator of the positive feedback regulation relationship between PLAG1 and the PI3K-Akt signaling pathway.

Increase in Chymase-Positive Mast Cells in Recurrent Pleomorphic Adenoma and Carcinoma Ex Pleomorphic Adenoma of the Parotid Gland

Incomplete excision of pleomorphic adenoma (PA) may result in recurrent pleomorphic adenoma (RPA). Furthermore, long-term neglected PA may become carcinoma ex pleomorphic adenoma (CXPA). In the present study, the relationships between mast cell-derived chymase and these tumors were examined. The tumor tissues of PA consisted of either or both glandular and fibrotic structures. Histological features of RPA were almost similar to those of PA, except that they showed multinodular structures. CXPA is composed of a mixture of PA and carcinoma. The main stromal cells in PA were myofibroblasts, whereas fibroblasts constituted the main cellular portion in the stromal tissue of RPA. Cancer-associated fibroblasts (CAFs) were present abundantly in CXPA. With increased VEGF expression, neovascularization tended to increase in RPA or CXPA. Compared with PA, chymase-positive mast cells, as well as chymase gene expression, were increased in the tumor tissues from patients with RPA or CXPA. SCF, TGFβ1, and PCNA-positive staining was widely observed in these tumor tissues. The above results suggest that mast cell-derived chymase through its direct or cooperative effects with other mediators may participate in the pathophysiology of RPA and CXPA.

Identification of new genes of pleomorphic adenoma

Pleomorphic adenoma is the most common salivary gland neoplasm with a variety of histologic appearances. Due to this diversity, precise preoperative diagnosis through fine needle aspiration cytology is difficult.This study sought to identify the differentially expressed genes in pleomorphic adenoma to aid precise diagnosis and clarify the mechanism of tumorigenesis.Suppressive subtractive hybridization was performed on pleomorphic adenoma tissues and the corresponding normal salivary gland tissues to screen of the differential expression of genes in pleomorphic adenoma.Four known genes (microfibrillar associated protein 4 [MFAP4], dystonin [DST], solute carrier family 35 [SLC35], and potassium channel tetramerization domain containing 15 [KCTD15]) were differentially expressed in the tumors compared with the genes in normal tissues. The expression profiles were further confirmed in 15 pleomorphic adenoma and corresponding normal salivary gland tissues by quantitative real-time reverse transcription-polymerase chain reaction.MFAP4, DST, SLC35, and KCTD15 gene expression could be potential biomarkers of pleomorphic adenoma for precise diagnosis.

Effect of Xylosyltransferase-I Silencing on Implanting Growth of Salivary Pleomorphic Adenoma

BACKGROUND Salivary pleomorphic adenoma is one of the most common salivary gland tumors. It has a relatively high tendency to recur and a high risk of malignant transformation. The present study aimed to study the effect of XT-I gene silencing on the implanting growth of salivary pleomorphic adenoma. MATERIAL AND METHODS Primary cultures of SPA cells and fibroblasts from the same patient were assessed. The adenovirus vector Ad-shRNA-XT-I was constructed and transfected into SPA cells. The expression of XT-I gene and XT-I protein was detected by real-time PCR and Western blot. The contents of proteoglycans were detected. The SPA cells transfected with Ad-shRNA-XT-I (group SPA-XT-I) and Ad-shRNA-HK (group SPA-HK), as well as without transfection (group SPA), were implanted into ADM scaffold with fibroblasts and then transferred into 18 BALB/C-nu nude mice for 3 months. RESULTS Primary cultures showed SPA cells were positive for human CK and S-100 protein and the fibroblasts were positive for human vimentin. The expressions of XT-I gene and protein were decreased by 51% and 51.31%, respectively. The content of proteoglycans was reduced by 48.45%. The results of the implanting growth in vitro and in vivo of nude mice indicated that no tumors grew in the SPA-XT-I group, whereas SPA grew in groups SPA-HK and SPA positive for human a-SMA, S-100 protein, and calponin. CONCLUSIONS XT-I gene silencing effectively inhibited the implanting growth of SPA.

Human Kallikrein 13 Expression in Salivary Gland Tumors

The human kallikrein 13 protein (hK13) is expressed in many normal tissues. Petraki et al have previously described presence of hK13 in salivary gland tissue, localized to duct epithelia and some acinar cells. The aim of this study was to determine whether hK13 is expressed in salivary gland tissues and salivary gland tumors (both benign and malignant), in order to compare normal with tumor tissues. Pleomorphic adenomas (PA), adenoid cystic carcinomas (ACC), polymorphous low grade adenocarcinomas (PLGA), acinic cell carcinomas (ACI), mucoepidermoid carcinomas (MEC) and adenocarcinomas not otherwise specified (ANOS) of both minor and major salivary glands were examined. The results of this study indicate that most salivary gland tumors show high levels of expression of hK13. Overall, staining in PA was significantly less than that seen in normal salivary gland tissue. PLGA, ACC and ANOS each stained significantly more than normal salivary gland tissue while MEC and ACI did not. Ductal cells and cells lining duct-like structures showed a higher intensity of staining than non-ductal cells in most tumors. Tumors which exhibited only non-ductal cells also exhibited cytoplasmic staining. In conclusion, we demonstrate the high expression of hK13 in several common salivary gland tumors.

[A Case of Rapidly Advancing G-CSF Producing Pleomorphic Carcinoma of the Breast Appearing as an Inflammatory Breast Cancer]

We report a rare case of pleomorphic carcinoma of the breast, suspected of being a granulocyte-colony stimulating factor (G-CSF)producing tumor, in a 75-year-old woman. She presented with a red and swollen breast, 3 weeks after undergoing core needle biopsy(CNB). Her leukocyte counts and C-reactive protein(CRP)levels were markedly high. At first, she was suspected to have an abscess and was initiated on a course of antibiotics. However, her condition rapidly deteriorated; therefore, she underwent an emergency mastectomy. Despite undergoing postoperative radiation therapy, 2 months after the operation, multiple metastatic foci were found in the lungs and liver, and she died of the disease 3 months after her first visit. After the operation, her leukocyte count had quickly returned to normal, but it increased as the disease progressed. These findings support the conclusion that this carcinoma was producing G-CSF. The final pathological diagnosis was G-CSF producing pleomorphic carcinoma of the breast.

Immunohistochemical Staining of Histological Fragments Derived from Salivary Gland Tumour Fine-Needle Biopsy Aspirates

OBJECTIVES

The aim of this study was to describe a method for analysing histological fragments derived from fine- needle aspirate biopsy (FNAB) of salivary gland tumours (SGTs), and to evaluate the use of immunohistochemistry (IHC) on them.

STUDY DESIGN

We reviewed all 509 FNAB pathology reports taken from SGTs at Helsinki University Hospital, Finland, between 1999 and 2009. In 51% of the cases (n = 209) "histo-fragments" had been obtained and 31 had been further analysed by IHC. Of these, 25 (81%) were available for review. We evaluated the benefit of IHC by relating its added value to the preoperative cytological diagnosis and its accuracy compared with the postoperative histological diagnosis.

RESULTS

Most of the samples analysed by IHC were assigned a malignant diagnosis, with 12 different types of malignancy represented. IHC was advantageous in 76% of the cases. In the 108 studies using IHC in this series, antibodies to 36 different antigens were used.

CONCLUSION

Analysis of histo-fragments in FNABs using IHC can be valuable in specific differential diagnostics and raises diagnostic accuracy in SGTs.

PLAG1: An Immunohistochemical Marker with Limited Utility in Separating Pleomorphic Adenoma from Other Basaloid Salivary Gland Tumors

OBJECTIVE

Fine-needle aspiration (FNA) diagnosis of salivary gland neoplasms is often challenging. Differentiating between pleomorphic adenomas (PA) and other basaloid neoplasms, especially basal cell adenoma (BCA) and adenoid cystic carcinoma (AdCC), can be difficult in cellular aspirates. PLAG1 (PA gene 1) is a proto-oncogene, which is frequently rearranged in PAs, leading to the aberrant expression of its protein. PLAG1 IHC expression has been reported to be positive in most PAs. The aim of this study was to evaluate the sensitivity and specificity of PLAG1 to differentiate PA from other basaloid neoplasms.

STUDY DESIGN

Immunohistochemical evaluation of PLAG1 was performed on 125 cases (52 FNAs and 73 surgical excisions). Nuclear staining of tumor cells was scored by the intensity and percentage of positive tumor cells. A combined score of >5 was defined as positive.

RESULTS AND CONCLUSION

The sensitivity (55%) and specificity (75%) of PLAG1 in diagnosing PA in FNAs is relatively modest thus limiting its diagnostic utility. BCAs and AdCCs showed PLAG1 false positivity, in surgical excision specimens and less so in FNAs. This may be due to limited sampling or tumor heterogeneity. Hence, PLAG1 is a modest marker for PAs in FNAs.

p63 Expression in Salivary Gland Tumors: Role ofΔNp73L in Neoplastic Transformation

To illustrate the role of p63 and its truncated variants in salivary gland tumors, 23 consecutive tumors and 6 normal salivary glands were studied immunohistochemically with anti-p63 antibody and by reverse transcriptase (RT) and nested polymerase chain reaction (PCR) to detect p63 isoform expression. Normal salivary glands: p63 antibody-stained basal and myoepithelial cells; by RT and nested PCR, the 2 main isoforms were present, whereas ΔNp73L was absent. Tumors: p63 antibody was positive in the following: Warthin tumor (WT) (3/3), oncocytoma (OC) (1/1), pleomorphic adenoma (PA) (7/7), polymorphous-low-grade adenocarcinoma (PLGA) (3/3), adenoid-cystic carcinoma (ADCC)(3/4), epithelial-myoepithelial-cell carcinoma (EMC) (1/1), and myoepithelial-cell carcinoma (MCC) (1/1). By RT and nested PCR all tumors expressed p63 irrespective of their morphologic differentiation. The ΔNp73L isoform was present in tumoral tissue but absent in normal salivary gland. These data suggest that p63, particularly its splice variant ΔNp73L, is involved in the neoplastic transformation of salivary glands.

PLAG1 expression is maintained in recurrent pleomorphic adenoma

The proto-oncogene (pleomorphic adenoma gene 1 (PLAG1)) is immunohistochemically overexpressed in pleomorphic adenoma (PA). Its expression in recurrent pleomorphic adenoma (RPA), however, has not been investigated. Since complex mechanisms are involved in tumor recurrence, the aim of this study was to investigate whether PLAG1 overexpression occurs in RPA. We studied PLAG1 protein expression in 40 PAs and 36 RPAs by immunohistochemistry. Cases with immunopositive cells were classified into two categories, between 10 and 50 % and >50 %. In both groups, PLAG1 expression was observed in both epithelial and myoepithelial cells. Of PAs, 37 cases (93 %) were positive, while this was the case in 34 RPA cases (94 %). Our findings suggest that in addition to morphological similarity, PA and RPA express PLAG1, which might play a role in tumor recurrence. Furthermore, as for PA, expression of PLAG1 can be considered a valuable diagnostic marker for RPA.

Glucocorticoid receptor subunit gene expression in parotid gland and adenomas

OBJECTIVE: The present study was undertaken to investigate the expressions of glucocorticoid receptor-α (GR-α) and -β (GR-β) messenger RNA (mRNA) in normal parotid and adenoma tissues.

STUDY DESIGN AND SETTING: Eighteen pleomorphic adenomas of the parotid gland and 12 parotid gland tissues adjacent to adenomas were studied by using real-time fluorescent quantitative reverse-transcription polymerase chain reaction method.

RESULTS: The expression of both GR-α and GR-β mRNA in parotid adenoma were higher than that in normal parotid glands ( P < 0.001), the GR-α/GR-β ratios in parotid adenoma were lower than that in normal parotid glands ( P < 0.001), and there were no differences of both GR-α and GR-β mRNA as well as GR-α/GR-β ratios in male and female ( P > 0.05).

CONCLUSION AND SIGNIFICANCE: Our results showed that the mRNA expression of both GR-α and GR-β were detectable in all studied specimens. The mRNA levels of these 2 GRs were higher, whereas the GR-α/GR-β ratios were lower in adenomas tissues than that in the parotid gland; no differences of these 2 GRs as well as GR-α/GR-β ratios were found between sexes. These data indicate that the relationship between the expressions of GRs and the clinical significance in parotid adenomas need further and profound investigation.

Human papillomavirus and salivary gland neoplasia: a p16INK4 immunohistochemical and in situ hybridisation study

OBJECTIVE

This study aimed to evaluate the association between human papillomavirus infection and salivary gland tumours in a Scottish cohort.

METHODS

Specimens from a range of salivary gland tumours operated on between 1997 and 2012 were studied. A tissue microarray constructed from tissue blocks was subjected to p16INK4 (cyclin-dependent kinase inhibitor 2A) immunohistochemistry and in situ hybridisation using probes specific for human papillomavirus, including types 16 and 18.

RESULTS

A total of 61 tumours (benign and malignant) were deemed suitable for the study. p16INK4 staining yielded three (4.9 per cent) positive samples: one small cell carcinoma, one squamous cell carcinoma and one poorly differentiated carcinoma. Human papillomavirus in situ hybridisation demonstrated a positive signal in the latter sample only (1.6 per cent).

CONCLUSION

This study demonstrated a very low human papillomavirus detection rate in salivary gland tumours. It can therefore be concluded that human papillomavirus infection is unlikely to play a role in salivary gland neoplasia. Rare human papillomavirus positive cases should be carefully evaluated to exclude the possibility of a metastatic lesion.

Recurrent salivary pleomorphic adenoma shows increased immunohistologic expression of bcl-2 oncoprotein

BACKGROUND

Internal cell biology, including apoptotic regulation, is presumed to play a key role in the development of recurrent pleomorphic adenoma (PA).

AIM

The aim of our study was to determine the relevance of B-cell lymphoma 2 (bcl-2) oncoprotein immunoexpression and distribution in primary PA, and its recurrence.

METHODS

Ten primary-non-recurrent, 14 primary-to-recur, and 28 recurrences of parotid PA patients aged 19-73 (mean 40.7±16.7) years were enrolled. The bcl-2 expression was compared between groups using a semi-quantitative histoscore, defined as the multiple of the percentage of cells by the intensity of immunostaining.

RESULTS

Widely varying bcl-2 immunoreaction was found in the epithelial areas of 91.7% of primary and 85.2% of recurrent PA. Similarly varying but much less, immunopositivity was found in the myxoid areas of 62.5% of primary and 71.4% of recurrent tumours. No obvious differences in the bcl-2 staining intensity or pattern of specific epithelial morphologic structures in either the primary-non-recurrent, primary-to-recur or recurrent tumours were found. In both the mesenchymal and epithelial areas of PA, the differences in bcl-2 immunohistoscore between the primary-non-recurrent and primary-to-recur groups were not statistically significant (P=0.62, respectively 0.51). In the mesenchymal areas, the study revealed a significantly increased histoscore in recurrent tumours compared to their corresponding primaries (P=0.01). Increased bcl-2 expression in recurrent PA suggests an exaggerated aggressiveness of that tumor.

CONCLUSION

The fact that a significant difference in the histoscore was found exclusively in the myxoid component seems to accord with the reported prevalence of the latter in recurrent and metastatic PA.

The Stem Cell Marker Bmi-1 Is Sensitive in Identifying Early Lesions of Carcinoma ex Pleomorphic Adenoma

In the present study, we evaluated and described the sensitivity of the stem cell marker B cell-specific moloney murine leukemia virus integration site 1 (Bmi-1) in identifying early lesions of carcinoma ex pleomorphic adenoma (CXPA). While invasive CXPAs are tumors with a prominent and easily recognizable malignant component, the identification of early carcinomatous changes in PA remains a diagnostic challenge due to the lack of objective morphological criteria. The immunohistochemical expression of Bmi-1 was assessed in both adenomatous and carcinomatous components of 9 CXPA cases at an early phase of histological progression (6 intracapsular and 3 minimally invasive) grouped according to the cellular differentiation as luminal (7 cases) or myoepithelial (2 cases). A selective nuclear expression of Bmi-1 was found exclusively in the malignant component of 8 cases (6 luminal type and 2 myoepithelial type), including intraductal carcinoma areas, except for 1 case in which scarce cells of the remnant PA were positive. Thus, Bmi-1 is expressed from the earliest morphologically detectable stages of PA malignant transformation. When faced with atypical features in PA, evaluation of Bmi-1 expression can provide more objective criteria for identification and diagnosis of early lesions of CXPA. This is applied to carcinomas with luminal or myoepithelial differentiation.

E-cadherin and α-SMA expression in the epithelial-mesenchymal transition of salivary glands pleomorphic adenomas

The pleomorphic adenoma, known also as mixed tumor of epithelioma with reshuffling stroma, is the most frequent salivary gland tumor, representing 45-75% of the total salivary gland tumors. In our study, we have investigated the immunohistochemical expression of E-cadherin and alpha-smooth muscle actin (α-SMA) in 15 cases of pleomorphic adenoma of salivary glands. We noticed the constant presence of E-cadherin reactivity at the level of luminal cells that cover the proliferative structures of ductal-cystic type, which gradually disappears to the periphery. At the level of epithelial proliferative solid areas, the reactivity for E-cadherin was inconstant and heterogeneous, while α-SMA expression increased. This aspect indicated the involving of epithelial-mesenchymal transition process in the evolution of pleomorphic adenoma.

Immunohistochemical features of lacrimal gland epithelial tumors

PURPOSE

To investigate the immunohistochemical features of ocular adnexal pleomorphic adenoma and adenoid cystic carcinoma.

DESIGN

Retrospective clinicopathologic study.

METHODS

Clinical records and microscopic slides of 7 cases of each tumor type were reviewed. Immunohistochemical probes for Ki-67 and p53, and newer nuclear markers MYB for adenoid cystic carcinoma and PLAG1 for pleomorphic adenoma, were employed.

RESULTS

Pleomorphic adenomas were asymptomatic, whereas adenoid cystic carcinomas were painful. No pleomorphic adenomas recurred; 4 adenoid cystic carcinomas recurred, resulting in 3 deaths. Unusual histopathologic variants for which immunohistochemistry proved useful included a myoepithelioma, an atypical pleomorphic adenoma, tubular and solid/basaloid variants of adenoid cystic carcinoma, and a morphologically heterogeneous adenoid cystic carcinoma of a Wolfring gland. For the pleomorphic adenomas, the average Ki-67 proliferation index was 3.8%; p53 was weakly staining, with an average positivity of 18.5%; PLAG1 was strongly positive in all cases; MYB was negative in 5 cases and weakly focally positive in 2 cases. For the adenoid cystic carcinomas, the average Ki-67 proliferation index was 29.1%; p53 stained positively and strongly with an average of 39%; none stained positively for PLAG1; and 6 out of 7 were MYB positive.

CONCLUSIONS

Between pleomorphic adenoma and adenoid cystic carcinoma, there was no overlap in Ki-67 positivity. Positivity for p53 showed overlap in only one lesion of each type. PLAG1 and MYB positivity were highly discriminating between pleomorphic adenoma and adenoid cystic carcinoma. Immunohistochemical analysis should be investigated further for its role in the evaluation of pleomorphic adenoma and adenoid cystic carcinoma.

New insight into benign tumours of major salivary glands by proteomic approach

Major salivary gland tumours are uncommon neoplasms of the head and neck. The increase of precise pre-operative diagnosis is crucial for their correct management and the identification of molecular markers would surely improve the required accuracy. In this study we performed a comparative proteomic analysis of fine needle aspiration fluids of the most frequent benign neoplasms of major salivary glands, namely pleomorphic adenoma and Warthin's tumour, in order to draw their proteomic profiles and to point out their significant features. Thirty-five patients submitted to parotidectomy were included in the study, 22 were identified to have pleomorphic adenoma and 14 Warthin's tumour. Fine needle aspiration samples were processed using a two-dimensional electrophoresis/mass spectrometry-based approach. A total of 26 differentially expressed proteins were identified. Ingenuity software was used to search the biological processes to which these proteins belong and to construct potential networks. Intriguingly, all Warthin's tumour up-regulated proteins such as Ig gamma-1 chain C region, Ig kappa chain C region and Ig alpha-1 chain C region and S100A9 were correlated to immunological and inflammatory diseases, while pleomorphic adenomas such as annexin A1, annexin A4, macrophage-capping protein, apolipoprotein E and alpha crystalline B chain were associated with cell death, apoptosis and tumorigenesis, showing different features of two benign tumours. Overall, our results shed new light on the potential usefulness of a proteomic approach to study parotid tumours and in particular up regulated proteins are able to discriminate two types of benign parotid lesions.

Carcinoma ex pleomorphic adenoma, with particular emphasis on early lesions

Carcinoma ex pleomorphic adenoma (CXPA) is a broad category of carcinomas of the salivary glands which includes at least 2 clinically relevant categories; one is referred here as early CXPA (ECXPA), the other as widely invasive CXPA. The former includes several histological patterns ranging from non-invasive/in situ/intraductal/intratubular, early invasive/extratubular/intracapsular and extracapsular (up to 6 mm). The latter includes any CXPA with invasion of >6 mm. The clinical behaviour of ECXPA is not aggressive and tends to overlap that of a pleomorphic adenoma (PA) which makes the histological report of carcinoma contradictory. These early malignant changes in PA are known since the 1970s but it has been the use of immunohistochemical and molecular genetic analysis for HER-2 and TP53 gene in the last decade that has clarified the genuine malignant nature of the cells. HER-2 and TP53 gene and protein are involved in the early stages of malignant transformation of PA. Moreover the immunohistochemical over-expression HER-2, p53 protein and Mib-1 proliferation marker may be useful markers to identify malignant areas in PA.

The involvement of growth differentiation factor 5 (GDF5) and aggrecan in the epithelial-mesenchymal transition of salivary gland pleomorphic adenoma

Pleomorphic adenoma is the most common salivary gland tumor with annual incidence of 2-3.5/100 000 in population. The histogenesis of salivary gland pleomorphic adenoma is still unclear. One concept sustains the existence of an epithelial-mesenchymal transitions (EMT) process in pleomorphic adenomas by which neoplastic epithelial cells transdifferentiate into mesenchymal cells and leading to tissue heterogeneity from this salivary gland neoplasia. Here we investigate by immunohistochemistry the expression of growth differentiation factor 5 (GDF5) and aggrecan in 15 cases of salivary gland pleomorphic adenomas. We found that both markers were present in normal salivary gland, mainly in the cells that line striated and intercalated ducts suggesting their involvement in the morphogenesis of this duct system. A constant positive reactivity for both markers was recorded in transition regions from tubular proliferative units to myxoid areas suggesting the involvement of an EMT process during the tumorigenesis of such salivary gland neoplasia. Also, both markers may be implicated in the transdifferentiation of neoplastic myoepithelial cells from the myxoid zones to lacuna cells of adjacent chondroid areas completing the morphology of this salivary gland tumor.

Usefulness of the melanoma antigen gene (MAGE) in making the differential diagnosis between pleomorphic adenoma and adenoid cystic carcinoma

OBJECTIVE

The aim of this study was to examine the clinical usefulness of the melanoma antigen gene (MAGE) in making the differential diagnosis between pleomorphic adenoma (PA) and adenoid cystic carcinoma (ACC). In addition, using real-time reverse transcriptase polymerase chain reaction (RT-PCR), we examined which melanoma antigen gene was actually expressed in each tumour.

MATERIALS AND METHOD

Immunohistochemical staining was performed on samples of paraffin-embedded tissue specimens. Fifty-eight patients were diagnosed as PA (n  =  31), ACC (n  =  17), and nontumoral salivary tissue (n  =  10) using MAGEA and MAGEA4. Using primers that could express MAGEA1, -A2, -A3, -A4, -A6, -A10, and -A12 subtypes, real-time RT-PCR was performed in three cases of PA and four cases of ACC that occurred in fresh tissues.

RESULT

We found no immunohistochemical expression of MAGEA or MAGEA4 in the nontumoral tissue. There was a mild degree of expression with no statistical significance in cases of PA. In ACC, however, in 17 cases (100%) and 16 cases (95%), there was a positive reaction to MAGEA and MAGEA4, respectively. In the RT-PCR analysis, PA showed no MAGE gene expression. However, both MAGEA3 and MAGEA4 were expressed in ACC.

CONCLUSION

These results suggest that MAGE could be used as a biologic marker in the differential diagnosis between PA and ACC. Our results also indicate that the expression of MAGE, as confirmed in the RT-PCR analysis, could be used as an alternative method for the early diagnosis of salivary gland tumours.

Carcinoma ex pleomorphic adenoma of the salivary glands: distinct clinicopathologic features and immunoprofiles between subgroups according to cellular differentiation

In carcinoma ex pleomorphic adenoma (CXPA), pleomorphic adenoma (PA) and diverse carcinoma components showing luminal (ductal) or non-luminal (myoepithelial) differentiation coexist. To elucidate the clinicopathological implications of cellular differentiation in CXPA and the potential role of p53, vascular endothelial growth factor (VEGF), c-erbB-2, c-kit, and glucose transporter 1 (Glut-1) in carcinogenesis, we analyzed 11 CXPAs with luminal differentiation (CXPAs-LD) and 6 CXPAs with non-luminal differentiation (CXPAs-NLD) and compared protein expressions in residual PAs and carcinomas by immunohistochemistry. Among the CXPAs-LD, 5 were invasive and 8 were histologically high-grade tumors. The 5-year survival rate was 72.7%. P53, c-erbB-2, VEGF, and Glut-1 were more immunoreactive in carcinoma components than in PAs (P = 0.008, 0.004, 0.002, and 0.024, respectively); c-erbB-2 overexpression was associated with high histological grade (P = 0.024). Carcinoma components frequently lacked c-kit expression (P = 0.009). CXPAs-NLD were all low-grade and invasive with a larger mean tumor size (5.2 cm) than CXPAs-LD (3.3 cm) (P = 0.040). The patients remained disease-free without significant immunohistochemical expression. The immunoprofiles and clinical course of CXPA differed according to cellular differentiation. Therefore, it is important to report the histological subtype and to assess potential biomarkers in diagnostic and therapeutic trials.

WT1 expression in salivary gland pleomorphic adenomas: a reliable marker of the neoplastic myoepithelium

Pleomorphic adenoma is a benign salivary gland neoplasm with a diverse morphology. This is considered to be a function of the neoplastic myoepithelium, which shows histological and immunophenotypical variability. Wilms' tumor 1 gene (WT1) protein, involved in bidirectional mesenchymal-epithelial transition, has been detected by reverse transcription PCR in salivary gland tumors showing myoepithelial-epithelial differentiation. The aim of this study was to investigate the immunoreactivity of WT1 in pleomorphic adenomas and to compare the pattern of staining with p63 and calponin, two reliable markers of myoepithelial cells. A total of 31 cases of pleomorphic adenoma were selected. The myoepithelium was classified as myoepithelial-like (juxtatubular and spindled), modified myoepithelium (myxoid, chondroid and plasmacytoid) and transformed myoepithelium (solid epithelioid, squamous and basaloid cribriform). Immunohistochemistry for WT1, p63 and calponin was assessed in each myoepithelial component, as well as in nonneoplastic myoepithelial cells and inner tubular epithelial cells. There was no immunostaining of tubular epithelial cells by any of the markers. In contrast to p63 and calponin, WT1 did not react with normal myoepithelial cells. Cytoplasmic WT1 staining was present in all pleomorphic adenomas, and in 29 cases (94%), >50% of neoplastic myoepithelial cells were highlighted. p63 and calponin stained the myoepithelium in 30 tumors. In comparison, 50% of cells were positive in 21 (68%) and 9 (29%) cases of p63 and calponin, respectively. Staining with WT1 showed less variability across the spectrum of myoepithelial differentiation with the difference most marked in the transformed myoepithelium. WT1 is a sensitive marker of the neoplastic myoepithelial cell in pleomorphic adenomas. The role of this protein in influencing the mesenchymal-epithelial state of cells suggests that WT1 and the myoepithelial cell have an important role in the histogenesis of pleomorphic adenomas.

Proliferative potential in benign mixed salivary gland tumors and its value in primary and recurrent neoplasms

OBJECTIVE. Mixed salivary gland tumors are characterized by a marked diversity in the cell proliferation. It course in the stromal component, and, especially in recurrent neoplasms, is not completely understood. This study evaluated cell proliferative potential, its value and the clinical course of primary and recurrent salivary gland pleomorphic adenomas (PA). MATERIALS AND METHODS. 322 benign salivary gland tumors were used in this study. The cell proliferation was estimated by Ki-67 expression levels. RESULTS. Ki-67 immunoreactivity showed a wide range of spectra; in the epithelial and stromal type of PA the cell proliferation had the value from 0.07±0.03 (95% CI 0.01-0.14) to 4.81±0.60 (95% CI 3.61-6.02) and from 0 to 0.79±0.11 (95% CI 0.57-1.00), respectively. The Ki-67 value was higher in recurrent tumors compared with primary, and the mean number of Ki-67-positive cells per visual microscopic field constituted 2.14±1.60 (95% CI 1.47-2.47) comparing with 1.43 (95% CI 0.97-1.55) revealed in primary tumors. CONCLUSION. Cell proliferation values correlate with a recurrence of neoplasm, and elevation of proliferation potential in the stromal component of recurrent PA is indicative of clinical course change for the worse.

Pleomorphic adenoma of the upper lip

Pleomorphic adenoma is the most common neoplasm of the salivary glands and is most commonly located in the parotis followed by the submandibular glands. Its localization in the minor salivary glands is mostly reported in the palate. Few publications report pleomorphic adenoma cases located in the lip. We present a 35-year-old male patient with a pleomorphic adenoma located in the upper lip.

[Expression of transforming growth factor-β(1) and Ki-67 nuclear antigen in salivary gland mucoepidermoid carcinoma]

OBJECTIVE

To investigate the expression and significance of transforming growth factor-β(1) (TGF-β(1)) and Ki-67 nuclear antigen in salivary gland mucoepidermoid carcinoma.

METHODS

The expression of TGF-β(1) and Ki-67 nuclear antigen in 20 cases of salivary gland pleomorphic adenoma and 45 cases of mucoepidermoid carcinoma were detected by the streptavidin-peroxidase immunohistochemical method.

RESULTS

Expression of TGF-β(1) (39/45) and Ki-67 nuclear antigen (43/45) in mucoepidermoid carcinoma was significantly higher than in pleomorphic adenoma (P < 0.05). TGF-β(1) expression was significantly higher in moderately/poorly differentiated mucoepidermoid carcinoma (16/16) than that in well differentiated mucoepidermoid carcinoma (23/29) and pleomorphic adenoma (12/20) (P < 0.05), but not different between well differentiated mucoepidermoid carcinoma (6/23) and pleomorphic adenoma (8/12) (P > 0.05). The expression of Ki-67 was increased with the increment of TGF-β(1) expression in mucoepidermoid carcinoma (P < 0.05).

CONCLUSIONS

The high expression of TGF-β(1) may play an important role in cell differentiation and malignant proliferation of mucoepidermoid carcinoma.

Expression of hormonal receptor in patients with metastasizing pleomorphic adenoma of the major salivary gland; a clinicopathological report of three cases

BACKGROUND

Metastasizing pleomorphic adenoma is an uncommon malignant tumor of the salivary gland demonstrating benign epithelial and modified myoepithelial elements intermingling with tissue of mucoid, myxoid, or chondroid appearance that inexplicably manifests local or distant metastasis.

OBJECTIVE

To determine the expression of hormonal receptor in the patients with metastasizing pleomorphic adenoma of the major salivary gland.

MATERIAL AND METHOD

Medical records, clinical and pathologic findings of three patients who were diagnosed as metastasizing pleomorphic adenoma were reviewed. The immunohistochemical stains for estrogen receptor, progesterone receptor, and Ki-67 were performed.

RESULTS

Three cases of metastasizing pleomorphic adenoma, clinically presenting as painless, gradually enlarged cervical lymph nodes were reported. The pathologic examinations of the cervical lymph nodes are morphologically and immunohistologically identical to the sialoadenectomy specimen. Immunohistochemical stains show positive reactivity to progesterone receptor but negative reactivity to estrogen receptor in both mesenchymal and epithelial components of pleomorphic adenoma.

CONCLUSION

These are the first reported cases of metastasizing pleomorphic adenoma of the major salivary glands associated with expression of progesterone receptor in both specimens of sialoadenectomy and lymph node biopsy. This finding supports the pathogenesis of benign metastasis of tumor. However, the role of hormonal receptor in the pathogenesis and treatment of salivary metastasizing pleomorphic adenoma should be further investigated.

Expression patterns and prognostic significance of inhibitor of apoptosis proteins in adenoid cystic carcinoma and pleomorphic adenoma of lachrymal gland

It has been widely reported that IAPs family are overexpressed in various malignancies, and their expression patterns are associated with clinical outcome of these diseases. Adenoid cystic carcinoma (ACC) of lachrymal gland is a malignant tumor with a poor prognosis, while, pleomorphic adenoma (PA) is the benign tumor of lachrymal gland epithelia. It was the first time that we investigated the expression profile of IAPs in tissues from ACC and PA, and evaluated the prognostic significance of IAPs. Paraffin-embedded tissues with 27 cases of ACC and 33 cases of PA were enrolled, and another 17 fresh frozen tissues were also collected. Expression of cIAP1, cIAP2, XIAP, Survivin and Livin in embedded tissues was analyzed by immunohistochemistry, and expression of five IAPs in fresh tissues was evaluated by semiquantitive RT-PCR and Western blot. Prognostic significance of IAPs with clinicopathological variables and outcome was then investigated with univariate and multivariate analysis. Survivin and cIAP2 expression in ACC were significantly higher than that of in PA (p < 0.05). cIAP1 and XIAP tended to show stronger expression in ACC than in PA, although the differences were not statistically significant. Livin expression was almost undetectable in both malignancy and benign lesion of lachrymal gland. Survivin expression in lachrymal tumors was localized in cytoplasm exclusively, and its expression was related to T staging and proliferative index in ACC, multivariate analysis demonstrated that Survivin was the only factor that could independently predict poor prognosis of ACC (RR = 3.681, 95%CI: 1.068-12.688, p = 0.039). Furthermore, Survivin expression was associated with progression of PA. Expression of cIAP1, cIAP2, XIAP and Survivin was higher in ACC than in PA tissues, however, only differential expression of Survivin and cIAP2 between ACC and PA was significant. Different prognosis between ACC and PA might be attributable to the different expression profiles of IAPs. Overexpression of Survivin in ACC was associated with poorer survival, which may have clinical impact on diagnosis and therapeutic considerations of this malignancy.

Upregulation of Igf and Wnt signalling associated genes in pleomorphic adenomas of the salivary glands in PLAG1 transgenic mice

The Pleomorphic adenoma gene 1 (PLAG1) is involved in various human neoplasias, including pleomorphic adenomas of the salivary glands. Moreover, the oncogenic role of PLAG1 was clearly demonstrated in two independent PLAG1 transgenic mouse founders, in which PLAG1 expression could be targeted to different tissues using the Cre/loxP system. MMTV-Cre-mediated targeted overexpression of PLAG1 in the salivary glands of double transgenic offspring mice, referred to as P1-MCre and P2-MCre mice, induced pleomorphic adenomas in this organ. Igf2, a genuine PLAG1 target gene, was highly upregulated in those tumours as well as in human pleomorphic adenomas of the salivary glands. These and previous observations in other PLAG1-induced tumours e.g. breast adenomyoepitheliomas emphasize the importance of Igf upregulation in such tumours. In this study, further evidence for the role of Igf2 in PLAG1-induced tumourigenesis, is reported. Inactivation of Igf2 in P1-MCre mice leads to a significant delay in tumour development. Since tumour development is not fully abrogated by inactivation of Igf2, other signalling pathways are likely to contribute to PLAG1-induced tumourigenesis as well. Further studies revealed that several genes such as H19, Dlk1, Gtl2, Igfbp2, Igfbp3 and genes involved in Wnt signalling, such as Wnt6, Cyclin D1 and beta-catenin are upregulated in P1-MCre mice in which Igf2 is inactivated. In conclusion, we clearly demonstrate upregulation of several genes associated with Igf and Wnt signalling in PLAG1-induced pleomorphic adenomas. Furthermore, inactivation of Igf2 does not affect upregulation of genes associated with Wnt signalling, which might suggest that both signalling pathways are involved.

Expression of epidermal growth factor receptor, transforming growth factor-alpha and Ki-67 in relationship to malignant transformation of pleomorphic adenoma

CONCLUSION

Quantitative assessment is more sensitive as a measure of cellular protein content as compared with standard optical density measurements. The data support the hypothesis that increased epidermal growth factor receptor (EGFR) and transforming growth factor (TGF)-alpha expression is associated with early events in malignant transformation of pleomorphic adenoma (PA).

OBJECTIVE

In the present study, we attempted to identify EGFR and TGF-alpha expression and Ki-67 index in carcinoma ex-pleomorphic adenoma (Ca ex-PA) and PA. We also compared the presence of EGFR and TGF-alpha and Ki-67 index with clinical data.

MATERIALS AND METHODS

The tissues were stained with monoclonal antibodies to EGFR, TGF-alpha and Ki-67. The results were analysed using quantitative immunohistochemical analysis. We also analysed the association of patients' prognosis with clinical parameters and the histological classification of the carcinomatous component.

RESULTS

As regards the association of patients' prognosis with EGFR staining and Ki-67 index, a significant increase was observed in patients who died or had residual disease compared with patients who were alive without disease. In the immunohistochemical analysis of EGFR and TGF-alpha and Ki67 index, a significant increase was observed in Ca ex-PA, especially with adenocarcinoma, compared with PA and sialadenitis.

CK7+/CK20- immunoexpression profile is typical of salivary gland neoplasia

AIMS

To evaluate cytokeratin (CK) 7/20 expression patterns in salivary gland neoplasia.

METHODS AND RESULTS

Formalin-fixed paraffin embedded tissue from 153 salivary gland tumours were evaluated for CK7/20 immunoreactivity. The tumours included pleomorphic adenoma (n = 24), myoepithelioma (n = 9), papillary cystadenoma (n = 3), oncocytoma (n = 2), adenoid cystic carcinoma (n = 22), mucoepidermoid carcinoma (n = 21), polymorphous low-grade adenocarcinoma (n = 21), carcinoma ex-pleomorphic adenoma (n = 11), acinic cell carcinoma (n = 17), epimyoepithelial carcinoma (n = 7), oncocytic carcinoma (n = 3), hyalinizing clear cell carcinoma (n = 1), papillary cystadenocarcinoma (n = 1), salivary duct carcinoma (n = 3), adenocarcinoma (not otherwise specified) (n = 4) and squamous carcinoma (n = 4). Immunohistochemical procedures were performed using monoclonal antibodies CK7 (OV-TL 12/30), CK20 (Ks 20.8) and M3515 cytokeratin (AE1/AE3) in the presence of appropriate controls. The results were expressed semiquantitatively, according to the estimated percentage of positive tumour cells: 1+, 5-25%; 2+, 26-75%; and 3+, 76-100%. All salivary gland neoplasms showed a CK7+/CK20- immunoprofile ranging from 5 to 100%. Squamous carcinoma showed negative CK7/20 immunoexpression.

CONCLUSIONS

Although the CK7/20 immunoprofile is not useful in distinguishing the various types of salivary gland neoplasms or between benign and malignant salivary gland tumours, it may facilitate differentiation of primary salivary gland neoplasia from metastatic tumours and squamous carcinoma, and the diagnosis of metastatic salivary gland tumours.

Glial fibrillary acidic protein and CD57 immunolocalization in cell block preparations is a useful adjunct in the diagnosis of pleomorphic adenoma

CONTEXT

The cytologic distinction between pleomorphic adenoma (PA) and adenoid cystic carcinoma (ACC) can be diagnostically challenging in aspirate smears. Hence a cytologic diagnosis of "atypical cytology" with a differential diagnosis including PA and ACC is occasionally rendered in a subset of salivary gland fine-needle aspirations.

OBJECTIVE

To evaluate the role of glial fibrillary acidic protein (GFAP) and CD57 expression in cell block material obtained during fine-needle aspiration procedure in differentiating PA from ACC.

DESIGN

We performed GFAP and CD57 immunostains on formalin-fixed, paraffin-embedded cell block sections of 26 salivary gland fine-needle aspiration cases with the following cytologic diagnoses: (1) PA (10 cases); (2) atypical cytology, cannot exclude ACC (8 cases); and (3) ACC (8 cases).

RESULTS

All 10 (100%) cases with cytologic diagnoses of PA were positive for GFAP, and 8 (80%) of 10 cases were positive for CD57; tissue follow-up confirmed the diagnosis of PA in all cases. All 8 (100%) cases with cytologic diagnosis of ACC were negative for both GFAP and CD57; tissue follow-up confirmed the diagnoses of ACC in all cases. Of the 8 cases with diagnoses of atypical cytology, 4 (50%) were negative and 4 (50%) were positive for both GFAP and CD57. Subsequent tissue follow-up in these cases revealed 4 cases of ACC (all negative for GFAP and CD57) and 4 cases of PA (all positive for GFAP and CD57).

CONCLUSIONS

Our results show that positive staining for GFAP and CD57 serves as a useful adjunct for the diagnosis of PA and helps to reduce the uncertainty in challenging cases.

Cyclin A expression and its diagnostic value in pleomorphic adenoma and carcinoma expleomorphic adenoma of the parotid gland

AIMS

To investigate cyclin A expression in pleomorphic adenoma (PA) and carcinoma expleomorphic adenoma (CXPA) of the parotid gland with a view to assessing its potential value as a diagnostic marker for CXPA.

METHODS AND RESULTS

Cyclin A expression in PA and CXPA was studied using semiquantitative immunohistochemistry. The epithelial component of the tumours expressed cyclin A in a statistically significantly (P < 0.005) higher number of CXPA cases (86%) compared with the PA cases (39%). Cyclin A was not expressed in normal salivary tissues of PA and CXPA.

CONCLUSIONS

High cyclin A expression is a useful marker for the pathological diagnosis of CXPA.

Pleomorphic adenoma and adenoid cystic carcinoma: in vitro study of the impact of TGFbeta1 on the expression of integrins and cytoskeleton markers of cell differentiation

Pleomorphic adenoma (PA) and adenoid cystic carcinoma (ACC) are the commonest benign and malignant salivary gland tumours respectively. Interactions between cells and extracellular matrix of PA and ACC, partially mediated by integrins, are important in their biology. The expression of integrins is regulated by numerous factors, amongst them, transforming growth factor beta1 (TGFbeta1). Our study investigated the effects of TGFbeta1 on the expression of integrin beta subunits in vitro and on the expression of cytoskeletal proteins of cells derived from PA and ACC. The expression of cytoskeletal differentiation markers and integrins was assessed using immunofluorescence. ELISA assays were employed to quantitate the expression integrins and MTT assays evaluated the mitochondrial activity of cells stimulated with TGFbeta1. PA cells showed increased expression of integrins and de novo expression of differentiation markers upon TGFbeta1 stimulation. ACC cells were less responsive to such stimulation. This may reflect important differences in the biological behaviour of benign and malignant cells.