Defining the relationship of salivary gland malignancies to novel cell subpopulations in human salivary glands using single nucleus RNA-sequencing

Salivary glands have essential roles in maintaining oral health, mastication, taste and speech, by secreting saliva. Salivary glands are composed of several types of cells, and each cell type is predicted to be involved in the carcinogenesis of different types of cancers including adenoid cystic carcinoma (ACC), acinic cell carcinoma (AciCC), salivary duct carcinoma (SDC), myoepithelial carcinoma (MECA) and other histology. In our study, we performed single nucleus RNA-seq on three human salivary gland samples to clarify the gene expression profile of each complex cellular component of the salivary glands and related these expression patterns to expression found in salivary gland cancers (SGC) to infer cell of origin. By single nucleus RNA-seq, salivary gland cells were stratified into four clusters: acinar cells, ductal cells 1, ductal cells 2 and myoepithelial cells/stromal cells. The localization of each cell group was verified by IHC of each cluster marker gene, and one group of ductal cells was found to represent intercalated ductal cells labeled with HES1. Furthermore, in comparison with SGC RNA-seq data, acinar cell markers were upregulated in AciCC, but downregulated in ACC and ductal cell markers were upregulated in SDC but downregulated in MECA, suggesting that markers of origin are highly expressed in some SGC. Cell type expressions in specific SGC histology are similar to those found in normal salivary gland populations, indicating a potential etiologic relationship.

Diagnostic accuracy of pan-TRK immunohistochemistry in differentiating secretory carcinoma from acinic cell carcinoma of salivary gland-A systematic review

BACKGROUND

Secretory carcinoma (SC) is a well-established salivary gland malignancy that has earned its popularity for its unique clinicopathological behavior. Although it is an indolent malignancy, few of them have been reported with high grade transformation making it mandatory to differentiate it from its prime histological mimicker, acinic cell carcinoma (AciCC). Recently, many studies have been directed toward validating the sensitivity and specificity of pan-TRK IHC for confirming ETV6::NTRK3 gene fusion in SCs involving salivary gland.

AIM

The aim of the present systematic review was to establish the diagnostic utility of pan-TRK immunostaining in histological differentiation of SC from AciCC.

MATERIAL AND METHODS

An electronic search was carried out using MEDLINE by PubMed, Scopus, Google scholar, Trip, Cochrane library and EMBASE databases. Articles in which SC assessed with pan-TRK immunohistochemical expressions were included for systematic review and their staining pattern (cytoplasmic, nuclear and/or combined), sensitivity, specificity, positive as well as negative predictive were gathered. Risk of bias was analyzed for each study using QUADAS-2 tool.

RESULTS

Thirteen eligible articles were included for the quantitative analysis, which revealed positive immunostaining of pan-TRK by nearly all the ETV6::NTRK3 fusion prevalent SCs alongside negative expression in almost all the cases of AciCC with 100% of sensitivity as well as specificity.

CONCLUSION

The evidence from the included studies supports that pan-TRK immunostaining could be used as a reliable preliminary screening tool for discerning SC from AciCC. PROSPERO No: CRD42022308913.

Short communication: Distribution of phospholipids in parotid cancer by matrix-assisted laser desorption/ionization imaging mass spectrometry

Background

Parotid cancer is relatively rare, and malignancy varies; therefore, novel markers are needed to predict prognosis. Recent advances in matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS), useful for visualization of lipid molecules, have revealed the relationship between cancer and lipid metabolism, indicating the potential of lipids as biomarkers. However, the distribution and importance of phospholipids in parotid cancer remain unclear.

Objective

This study aimed to use MALDI-IMS to comprehensively investigate the spatial distribution of phospholipids characteristically expressed in human parotid cancer tissues.

Methods

Tissue samples were surgically collected from two patients with parotid cancer (acinic cell carcinoma and mucoepidermoid carcinoma). Frozen sections of the samples were assessed using MALDI-IMS in both positive and negative ion modes, with an m/z range of 600–1000. The mass spectra obtained in the tumor and non-tumor regions were compared and analyzed. Ion images corresponding to the peak characteristics of the tumor regions were visualized.

Results

Several candidate phospholipids with significantly different expression levels were detected between the tumor and non-tumor regions. The number of unique lipid peaks with significantly different intensities between the tumor and non-tumor regions was 95 and 85 for Cases 1 and 2, respectively, in positive ion mode, and 99 and 97 for Cases 1 and 2, respectively, in negative ion mode. Imaging differentiated the characteristics that phospholipids were heterogeneously distributed in the tumor regions.

Conclusion

Phospholipid candidates that are characteristically expressed in human parotid cancer tissues were found, demonstrating the localization of their expression. These findings are notable for further investigation of alterations in lipid metabolism of parotid cancer and may have potential for the development of phospholipids as biomarkers.

ANGPTL4 accelerates KRASG12D-Induced acinar to ductal metaplasia and pancreatic carcinogenesis

Oncogenic KRASG12D induces neoplastic transformation of pancreatic acinar cells through acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN), and drives pancreatic ductal adenocarcinoma (PDAC). Angiopoietin-like 4 (ANGPTL4) is known to be involved in the regulation of cancer growth and metastasis. However, whether ANGPTL4 affects KRASG12D-mediated ADM and early PDAC intervention remains unknown. In the current study, we investigated the role of ANGPTL4 in KRASG12D-induced ADM, PanIN formation, and PDAC maintenance. We found that ANGPTL4 was highly expressed in human and mouse ADM lesions and contributed to the promotion of KRASG12D-driven ADM in mice. Consistently, ANGPTL4 rapidly induced ADM in three-dimensional culture of acinar cells with KRAS mutation and formed ductal cysts that silenced acinar genes and activated ductal genes, which are characteristic of in vivo ADM/PanIN lesions. We also found that periostin works as a downstream regulator of ANGPTL4-mediated ADM/PDAC. Genetic ablation of periostin diminished the ADM/PanIN phenotype induced by ANGPTL4. A high correlation between ANGPTL4 and periostin was confirmed in human samples. These results demonstrate that ANGPTL4 is critical for ADM/PanIN initiation and PDAC progression through the regulation of periostin. Thus, the ANGPTL4/periostin axis is considered a potential target for ADM-derived PDAC.

Secretory carcinoma of salivary glands at the National Cancer Institute: A 20-year retrospective clinical, pathological, immunohistochemical and molecular study

OBJECTIVES

This study aim was to review cases of acinic cell carcinoma (the main differential diagnosis of secretory carcinoma) that were diagnosed and treated at the National Cancer Institute of Brazil (INCA) between 1996 and 2016. The primary objective was to identify underdiagnosed cases of secretory carcinoma via a clinical, immunopathological and molecular reassessment.

MATERIALS AND METHODS

This is a cross sectional study, with retrospective data collection from medical records and histological specimen review, with staining for periodic acid-Schiff (PAS) and PAS with diastase, immunohistochemistry for S-100, mammaglobin, and DOG-1, and droplet digital RT-PCR for ETV6-NTRK3. The Research Ethics Committee approved this study, and the patients allowed their participation through informed consent.

RESULTS

Eighty-three cases of acinic cell carcinoma were diagnosed and treated in the specified period at INCA, of which, seven had their diagnosis changed to secretory carcinoma.

CONCLUSION

The present study adds seven cases of secretory carcinoma to the literature, contributing to a better understanding of the epidemiological, histological, immunohistochemical and molecular characteristics of this recently described tumor. Also, the use of a comprehensive diagnostic approach, including immunohistochemical and molecular methods, along with classical morphological studies, allowed the reclassification of acinic cell carcinoma to secretory carcinoma.

PYK2 Is Involved in Premalignant Acinar Cell Reprogramming and Pancreatic Ductal Adenocarcinoma Maintenance by Phosphorylating β-CateninY654

BACKGROUND & AIMS

Identification and validation of new functionally relevant and pharmacologically actionable targets for pancreatic ductal adenocarcinoma (PDAC) remains a great challenge. Premalignant acinar cell reprogramming (acinar-to-ductal metaplasia [ADM]) is a precursor of pancreatic intraepithelial neoplasia (PanIN) lesions that can progress to PDAC. This study investigated the role of proline-rich tyrosine kinase 2 (PYK2) in mutant Kras-induced and pancreatitis-associated ADM and PanIN formation, as well as in PDAC maintenance.

METHODS

Genetically engineered mouse models of mutant Kras (glycine 12 to aspartic acid) and Pyk2 deletion were used for investigating the role of PYK2 in PDAC genesis in mice. In vitro ADM assays were conducted using primary pancreatic acinar cells isolated from mice. Immunohistochemistry, immunofluorescence, and a series of biochemical experiments were used to investigate upstream regulators/downstream targets of PYK2 in pancreatic carcinogenesis. PDAC cell line xenograft experiments were performed to study the role of PYK2 and its downstream target in PDAC maintenance.

RESULTS

PYK2 was increased substantially in ADM lesions induced by mutant Kras or inflammatory injury. Pyk2 deletion remarkably suppressed ADM and PanIN formation in a mutant Kras-driven and pancreatitis-associated PDAC model, whereas PYK2 knockdown substantially inhibited PDAC cell growth in vitro and in nude mice. This study uncovered a novel yes-associated protein 1/transcriptional co-activator with PDZ binding motif/signal transducer and activator of transcription 3/PYK2/β-catenin regulation axis in PDAC. Our results suggest that PYK2 contributes to PDAC genesis and maintenance by activating the Wnt/β-catenin pathway through directly phosphorylating β-cateninY654.

CONCLUSIONS

The current study uncovers PYK2 as a novel downstream effector of mutant KRAS signaling, a previously unrecognized mediator of pancreatitis-induced ADM and a novel intervention target for PDAC.

Immunohistochemistry with a pan-TRK antibody distinguishes secretory carcinoma of the salivary gland from acinic cell carcinoma

AIMS

Secretory carcinoma (previously known as mammary analogue secretory carcinoma) is characterised by ETV6 rearrangements, most often ETV6-NTRK3 fusion. Given its histological overlap with other salivary gland tumours, secretory carcinoma can be difficult to diagnose without genetic confirmation. A recently developed pan-TRK antibody shows promise for identifying tumours with NTRK fusions. The aim of this study was to evaluate the utility of pan-TRK immunohistochemistry in distinguishing secretory carcinoma from mimics.

METHODS AND RESULTS

We examined whole-tissue sections from 86 tumours, including 14 secretory carcinomas (12 parotid primaries and one buccal primary, and one metastasis; five with ETV6 rearrangement confirmed by fluorescence in-situ hybridisation, and one with ETV6-NTRK3 fusion and one with ETV6-RET fusion detected by targeted sequencing), 14 acinic cell carcinomas, 18 polymorphous adenocarcinomas, 20 low-grade mucoepidermoid carcinomas, and 20 pleomorphic adenomas. Immunohistochemistry was performed with a pan-TRK rabbit monoclonal antibody. Pan-TRK staining was detected in nine (64%) secretory carcinomas, all with a nuclear pattern and four with diffuse staining (>50% of cells). Among other tumour types, pan-TRK immunoreactivity was observed in all (100%) pleomorphic adenomas (particularly myoepithelial cell-rich, myxoid areas), 15 (83%) polymorphous adenocarcinomas, and four (20%) low-grade mucoepidermoid carcinomas, all with predominantly membranous/cytoplasmic immunoreactivity; only six cases showed focal (<10%) nuclear staining. All acinic cell carcinomas were entirely negative.

CONCLUSIONS

Although pan-TRK expression is not entirely sensitive or specific for secretory carcinoma, nuclear staining distinguishes secretory carcinoma from mimics. Acinic cell carcinomas are negative for pan-TRK, though membranous expression of TRK is common in other salivary gland neoplasms. The lack of pan-TRK immunoreactivity in a subset of secretory carcinomas may suggest non-NTRK fusion partners.

Strong triaxial coupling and anomalous Poisson effect in collagen networks

While cells within tissues generate and sense 3D states of strain, the current understanding of the mechanics of fibrous extracellular matrices (ECMs) stems mainly from uniaxial, biaxial, and shear tests. Here, we demonstrate that the multiaxial deformations of fiber networks in 3D cannot be inferred solely based on these tests. The interdependence of the three principal strains gives rise to anomalous ratios of biaxial to uniaxial stiffness between 8 and 9 and apparent Poisson's ratios larger than 1. These observations are explained using a microstructural network model and a coarse-grained constitutive framework that predicts the network Poisson effect and stress-strain responses in uniaxial, biaxial, and triaxial modes of deformation as a function of the microstructural properties of the network, including fiber mechanics and pore size of the network. Using this theoretical approach, we found that accounting for the Poisson effect leads to a 100-fold increase in the perceived elastic stiffness of thin collagen samples in extension tests, reconciling the seemingly disparate measurements of the stiffness of collagen networks using different methods. We applied our framework to study the formation of fiber tracts induced by cellular forces. In vitro experiments with low-density networks showed that the anomalous Poisson effect facilitates higher densification of fibrous tracts, associated with the invasion of cancerous acinar cells. The approach developed here can be used to model the evolving mechanics of ECM during cancer invasion and fibrosis.

Expression of Mucin 1 in salivary gland tumors and its correlation with clinicopathological factors

This study aimed to detect the expression of Mucin 1 (MUC1) in acinic cell carcinoma (AciCC) of salivary gland and to explore the relationship between MUC1 and clinicopathological factors of AciCC of salivary gland. Patients with salivary gland tumors who were treated at our hospital were enrolled in this study. The pathological sections collected from all subjects were classified by histological examinations. In addition, 40 cases of primary salivary gland AciCC tissues were selected and classified into experimental group, whereas 40 cases of normal salivary gland (NSG) tissues were selected and classified into control group. MUC1 positive cells in both experimental and control groups were detected by immunohistochemistry assays, while all clinical data were analyzed statistically. The results showed that MUC1 was only expressed in the ductal epithelium of NSG and distributed at the apical side of the cell membrane. In primary salivary gland AciCC tissues, scattered expressions of MUC1 were found both on the cell membrane and in the cytoplasm of tumor cells, and sometimes even in the cell nuclei, thus completely eliminating the polarized distribution of MUC1 expressions. The percentage of MUC1 positive cells in experimental group was significantly higher than that in control group (P < 0.05). In addition, the expression of MUC1 in salivary gland AciCC was correlated with gender, age, histological type, lesion location, cervical lymph node metastasis, local recurrence, and distant metastasis. In conclusion, MUC1 is related to the occurrence and development of salivary gland AciCC. Therefore, MUC1 may be used as a novel tumor marker in the clinical diagnosis and treatment of salivary gland AciCC.

Enhancer hijacking activates oncogenic transcription factor NR4A3 in acinic cell carcinomas of the salivary glands

The molecular pathogenesis of salivary gland acinic cell carcinoma (AciCC) is poorly understood. The secretory Ca-binding phosphoprotein (SCPP) gene cluster at 4q13 encodes structurally related phosphoproteins of which some are specifically expressed at high levels in the salivary glands and constitute major components of saliva. Here we report on recurrent rearrangements [t(4;9)(q13;q31)] in AciCC that translocate active enhancer regions from the SCPP gene cluster to the region upstream of Nuclear Receptor Subfamily 4 Group A Member 3 (NR4A3) at 9q31. We show that NR4A3 is specifically upregulated in AciCCs, and that active chromatin regions and gene expression signatures in AciCCs are highly correlated with the NR4A3 transcription factor binding motif. Overexpression of NR4A3 in mouse salivary gland cells increases expression of known NR4A3 target genes and has a stimulatory functional effect on cell proliferation. We conclude that NR4A3 is upregulated through enhancer hijacking and has important oncogenic functions in AciCC.

Extracellular Histones Activate Plasma Membrane Toll-Like Receptor 9 to Trigger Calcium Oscillations in Rat Pancreatic Acinar Tumor Cell AR4-2J

In acute pancreatitis, histones are released by infiltrating neutrophils, but how histones modulate pancreatic acinar cell function has not been investigated. We have examined histone modulation of rat pancreatic acini and pancreatic acinar tumor cell AR4-2J by calcium imaging. Histones were found to have no effect on calcium in pancreatic acini but blocked calcium oscillations induced by cholecystokinin or acetylcholine. Both mixed (Hx) and individual (H1, H2A, H2B, H3, H4) histones induced calcium oscillations in AR4-2J. RT-PCR and Western blot verified the expression of histone-targeted Toll-like receptor (TLR) 2, 4 and 9. Immunocytochemistry identified TLR2/TLR4 on apical plasma membrane and TLR9 in zymogen granule regions in pancreatic acini. TLR2 was found on neighboring and TLR9 on peripheral plasma membranes, but TLR4 was in the nucleus in AR4-2J clusters. Neither TLR2 agonist zymosan-A nor TLR4 agonist lipopolysaccharide had any effect on calcium, but TLR9 agonist ODN1826 induced calcium oscillations; TLR9 antagonist ODN2088 blocked H4-induced calcium oscillations in AR4-2J, which also disappeared after treatment of AR4-2J with glucocorticoid dexamethasone, with concurrent TLR9 migration from plasma membrane to cell interiors. TLR9 down regulation with siRNA suppressed H4-induced calcium oscillations. These data together suggest that extracellular histones activate plasma membrane TLR9 to trigger calcium oscillations in AR4-2J cells.

The screening and electron microscopy observation of mammary analogue secretory carcinoma in Chinese

Mammary analogue secretory carcinoma of salivary gland (MASC) is a tumor with histopathologic and immunophenotypic features mimicking secretory carcinoma of the breast harboring the ETV6 split. The expression of mammaglobin, S-100, Ki-67, P63 and ETV6 split were detected in twelve cases of acinar cell carcinoma and fourteen cases of mammary analogue secretory carcinoma of salivary gland by immunohistochemistry and fluorescence in situ hybridization respectively. The expression of ETV6 gene split was detected in fourteen mammary analogue secretory carcinomas of salivary gland with positive expression of mammaglobin. Eight of mammary analogue secretory carcinomas of salivary gland also tested positive for the ETV6 gene split via fluorescence in-situ hybridization (FISH). The concordance rate of the immunohistochemistry and FISH was 72.3%. Mammaglobin and ETV6 gene split detection could help to distinguish mammary analogue secretory carcinoma of salivary gland. The mammary analogue secretory carcinoma of salivary gland specimens were also examined under transmission electron microscope. And apical junctional complexes were observed in the loosely connected tumor cells.

[Clinicopathologic characterisitics of pancreatic acinar cell carcinomas]

Objective: To investigate clinical, pathological and immunohistochemical features of pancreatic acinar cell carcinoma. Methods: A retrospective review of surgical and pathological databases between 2011 and 2016 at PLA General Hospital was collected and 14 cases of acinar cell carcinoma (ACC) of the pancreas were identified. EnVision immunohistochemistry was used to detect the expression of Trypsin, bcl-10 and cytokeratin(CK) proteins. Results: The patients included nine cases of pure ACC, 3 cases of mixed acinar ductal carcinoma, 1 case of mixed acinar-neuroendocrine carcinoma and acinar-ductal-neuroendocrine carcinoma, respectively. Tumors involved different anatomic locations of the pancreas, including eight involving the head of pancreas, four in the body and tail, one in the uncinate process and one in a heterotopic pancreas. Two patients had lymph node and liver metastases before surgery. Microscopically, the tumor was hypercellular with less fibroblastic proliferation and tumor cells arranged in acinar or solid pattern. The well differentiated tumor cells showed eosinophilic, granular cytoplasm with single prominent nucleoli, while the poorly differentiated tumor cells tended to grow in solid sheets. Immunohistochemically, the tumor cells were positive for pan-cytokeratin (14/14), Trypsin (12/14) and bcl-10 (11/14). Stains for CK7 and CK19 were negative (11/14 and 3/4). According to the pTNM staging, there were 7 cases at stageⅠ, 3 at stage ⅡA, 3 at stage Ⅲ and 1 at stage Ⅳ. With average postoperative follow-up of 6-58 months, the median disease-free survival time was 16 months. Conclusions: Pancreatic acinar cell carcinoma is a rare and relatively indolent malignant tumor with characteristic histopathological and immunohistochemical features. Accurate pathological diagnosis plays an important role in patients' treatment and evaluation of prognosis.

Overexpression of SOX11 and TFE3 in Solid-Pseudopapillary Neoplasms of the Pancreas

OBJECTIVES

To characterize the expression of SOX11 and TFE3 proteins in solid-pseudopapillary neoplasms (SPNs) and their histologic mimickers.

METHODS

Immunohistochemistry for SOX11, TFE3, and β-catenin was performed on 31 cases of surgically resected SPNs. Neuroendocrine tumors, acinar cell carcinomas, and pancreatoblastomas served as controls.

RESULTS

Nuclear immunoreactivity for SOX11 was detected in all SPNs and five of 31 control tumors. Nuclear immunoreactivity for TFE3 was detected in 30 SPNs and three control tumors. Nuclear immunoreactivity for β-catenin was detected in all SPNs and four control tumors. The combination of three markers as immunohistochemical panels resulted in optimal sensitivity and specificity.

CONCLUSIONS

Both SOX11 and TFE3 were overexpressed in SPNs and may be involved in the pathogenesis. Clinically, SOX11 and TFE3 can be potentially used as diagnostic markers in distinguishing indeterminate SPNs from their histologic mimickers.

Genome-wide genetic and epigenetic analyses of pancreatic acinar cell carcinomas reveal aberrations in genome stability

Pancreatic acinar cell carcinoma (ACC) is an aggressive exocrine tumor with largely unknown biology. Here, to identify potential targets for personalized treatment, we perform integrative genome-wide and epigenome-wide analyses. The results show frequently aberrant DNA methylation, abundant chromosomal amplifications and deletions, and mutational signatures suggesting defective DNA repair. In contrast to pancreatic ductal adenocarcinoma, no recurrent point mutations are detected. The tumor suppressors ID3, ARID1A, APC, and CDKN2A are frequently impaired also on the protein level and thus potentially affect ACC tumorigenesis. Consequently, this work identifies promising therapeutic targets in ACC for drugs recently approved for precision cancer therapy.

TP53 alterations in pancreatic acinar cell carcinoma: new insights into the molecular pathology of this rare cancer

The molecular alterations of pancreatic acinar cell carcinomas (ACCs) are poorly understood and have been reported as being different from those in ductal adenocarcinomas. Loss of TP53 gene function in the pathogenesis of ACCs is controversial since contradictory findings have been published. A comprehensive analysis of the different possible genetic and epigenetic mechanisms leading to TP53 alteration in ACC has never been reported and hence the role of TP53 in the pathogenesis and/or progression of ACC remains unclear. We investigated TP53 alterations in 54 tumor samples from 44 patients, including primary and metastatic ACC, using sequencing analysis, methylation-specific multiplex ligation probe amplification, fluorescence in situ hybridization, and immunohistochemistry. TP53 mutations were found in 13 % of primary ACCs and in 31 % of metastases. Primary ACCs and metastases showed the same mutational profile, with the exception of one case, characterized by a wild-type sequence in the primary carcinoma and a mutation in the corresponding metastasis. FISH analysis revealed deletion of the TP53 region in 53 % of primary ACCs and in 50 % of metastases. Promoter hypermethylation was found in one case. The molecular alterations correlated well with the immunohistochemical findings. A statistically significant association was found between the combination of mutation of one allele and loss of the other allele of TP53 and worse survival.

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.

PTEN loss and ERG protein expression are infrequent in prostatic ductal adenocarcinomas and concurrent acinar carcinomas

BACKGROUND

Prostatic ductal adenocarcinoma is an unusual and aggressive morphologic subtype of prostate cancer. PTEN gene deletion and ERG gene rearrangement are among the most common genomic changes in acinar prostate cancers. Though ductal adenocarcinoma most commonly occurs with synchronous usual-type acinar adenocarcinoma, little is known about the molecular phenotype of these mixed tumors.

METHODS

We used genetically validated immunohistochemistry (IHC) assays to assess PTEN and ERG status in a group of 37 surgically treated ductal adenocarcinomas and 18 synchronous acinar adenocarcinomas where we have previously reported ERG gene rearrangement status by fluorescence in situ hybridization (FISH). A group of 34 stage and grade-matched pure acinar adenocarcinoma cases was studied as a control.

RESULTS

ERG IHC was highly concordant with ERG FISH results, with 100% (36/36) concordance among ductal adenocarcinomas and 91% (31/34) concordance among 34 pure acinar carcinomas. Similar to previous FISH results, ERG expression by IHC was significantly less common among ductal adenocarcinomas (11% or 4/37) and their synchronous acinar tumors (6% or 1/18) compared to matched pure acinar adenocarcinoma cases (50% or 17/34; P = 0.0005 and 0.002, respectively). PTEN loss by IHC was also less common among ductal adenocarcinomas (18% or 6/34) and their synchronous acinar tumors (22% or 4/18) compared to matched pure acinar carcinomas (50% or 17/34; P = 0.01 and 0.08, respectively). As expected, PTEN loss was enriched among ERG positive compared to ERG-negative tumors in the pure acinar tumor control group (2.5-fold enrichment; P = 0.04) however this was not observed among the ductal adenocarcinomas (1.5 fold enrichment; P = NS). Of ductal adenocarcinomas with an evaluable synchronous acinar component, ERG status was concordant in 94% (17/18) and PTEN status was concordant in 94% (16/17).

CONCLUSIONS

Based on PTEN and ERG, ductal adenocarcinomas and their concurrent acinar carcinomas may be clonally related in some cases and show important molecular differences from pure acinar carcinoma.

Diagnostic role of DOG1 and p63 immunohistochemistry in salivary gland carcinomas

BACKGROUND

The differential diagnosis of salivary carcinomas is always difficult and challenging. Salivary neoplasms often shows more than one growth pattern and significant morphologic variability may exist within a single tumor and between different tumors. The aim of this study was to examine the role of DOG1 (discovered on gastrointestinal tumor-1) and p63 immunohistochemistry in the diagnosis and differential diagnosis of salivary carcinomas.

METHODS

we examined the expression of DOG1 and p63 immunohistochemistry in 33 mucoepidermoid carcinomas (MEC), 9 acinic cell carcinomas (ACC), 10 adenoid cystic carcinomas (AdCC) and 4 myoepithelial carcinomas.

RESULTS

All ACC showed strong to moderate positivity for DOG1 (P=0.001) and all were totally negative for p63. All MEC expressed strong to moderate positivity for p63 (P=0.001) while only (9.1%) were weak to moderately positive for DOG1. (80%) AdCC were moderately positive for DOG1 in ductal and myoepithelial components and (100%) showed moderate positivity for p63 in myoepithelial cells only (P=0.001). All myoepithelial carcinomas were DOG1 negative, 2 (50%) were weakly positive for p63 while the other 2 were moderately positive (P=0.5).

CONCLUSION

DOG1 is a sensitive marker in the diagnosis of acinic cell carcinoma, p63 is sensitive in the diagnosis of mucoepidermoid carcinoma, the combined use of both markers is helpful and statistically significant in the differential diagnosis of acinic cell carcinoma versus mucoepidermoid carcinoma, both markers can help in the diagnosis of adenoid cystic carcinoma but they have no role in the diagnosis of myoepithelial carcinoma.

Comprehensive genomic profiling of pancreatic acinar cell carcinomas identifies recurrent RAF fusions and frequent inactivation of DNA repair genes

Pancreatic acinar cell carcinomas (PACC) account for approximately 1% (∼500 cases) of pancreatic cancer diagnoses annually in the United States. Oncogenic therapuetic targets have proven elusive in this disease, and chemotherapy and radiotherapy have demonstrated limited efficacy against these tumors. Comprehensive genomic profiling of a large series of PACCs (n=44) identified recurrent rearrangements involving BRAF and RAF1 (CRAF) in approximately 23% of tumors. The most prevalent fusion, SND1-BRAF, resulted in activation of the MAPK pathway, which was abrogated with MEK inhibition. SND1-BRAF-transformed cells were sensitive to treatment with the MEK inhibitor trametinib. PACCs lacking RAF rearrangements were significantly enriched for genomic alterations, causing inactivation of DNA repair genes (45%); these genomic alterations have been associated with sensitivity to platinum-based therapies and PARP inhibitors. Collectively, these results identify potentially actionable genomic alterations in the majority of PACCs and provide a rationale for using personalized therapies in this disease.

SIGNIFICANCE

PACC is genomically distinct from other pancreatic cancers. Fusions in RAF genes and mutually exclusive inactivation of DNA repair genes represent novel potential therapeutic targets that are altered in over two thirds of these tumors.

[Correlation of caveolin-1 expression with clinicopathologic features and prognosis in patients with lung adenocarcinoma]

OBJECTIVE

To study the expression, clinicopathologic correlation and prognostic significance of caveolin-1 in lung adenocarcinomas(LAC).

METHODS

Immunohistochemical study (EnVision method) for caveolin-1 and TTF-1 was carried out in 185 cases of LAC encountered during the period from 2005 to 2010. The correlation between caveolin-1 expression and various clinicopathologic parameters was analyzed statistically.

RESULTS

The rate of caveolin-1 expression in the 185 cases of LAC was 26.5% (49/185) and significantly lower than that in normal lung tissue (P<0.01). There was also higher rate of caveolin-1 expression in male patients (P=0.004), smokers (P=0.006), tumors larger than 3.5 cm (P=0.048), predominantly solid tumor subtype (P=0.025), high tumor grade (P=0.044), tumors with vascular invasion (P=0.019), lymph node metastasis (P=0.030), recurrence (P=0.021) and high clinical stage (P=0.027). The expression level of caveolin-1 in TTF1-negative cases was significantly higher than that in TTF1-positive cases and caveolin-1 expression also negatively correlated with TTF-1 expression in LAC (r=-0.154, P=0.037). The five-year overall survival rate of patients with caveolin-1 positive tumors was lower than that in caveolin-1 negative group (P<0.01).Univariate analysis indicated the expression level of caveolin-1 and TTF-1 (P<0.01), histologic subtype (P=0.002), tumor grade (P=0.002), tumor size (P=0.009), vascular invasion (P=0.019), lymph node metastasis (P=0.018), recurrence (P=0.032) and clinical stage (P=0.024) correlated with the survival of patients with LAC. COX multivariate analysis revealed that LAC with caveolin-1 positive expression, TTF-1 negative expression and high tumor grade carried a significantly unfavorable prognosis.

CONCLUSION

Caveolin-1 expression correlates with histologic subtype, tumor grade, invasiveness and metastatic potential of LAC. The detection of caveolin-1 in LAC is helpful in predicting prognosis.LAC with caveolin-1 expression carries a poor prognosis.

A rare malignancy of the parotid gland in a 13-year-old Taiwanese boy: case report of a mammary analogue secretory carcinoma of the salivary gland with molecular study

Mammary analogue secretory carcinoma (MASC) is a recently described malignancy of the salivary glands characterized by an ETV6-NTRK3 (EN) fusion gene. Morphologically, MASC is sometimes difficult to distinguish from acinic cell carcinoma. Consequently, identifying the chromosomal translocation is essential for diagnosis. We present a case of parotid gland MASC in a 13-year-old boy. To the best of our knowledge, this is the youngest case reported in the literature. Histologic evaluation showed a tumor composed of microcysts, tubular structures, solid nests, or papillary architecture, with secretions within the lumens of the cysts or tubules. Immunohistochemically, tumor cells showed diffuse positive staining of S-100 protein, cytokeratin 19, and vimentin. ETV6 rearrangement was detected by fluorescence in situ hybridization and EN fusion transcripts were verified by reverse transcription (RT-PCR) assay.

α-Methylacyl-CoA racemase (P504S) is a useful marker for the differential diagnosis of solid pseudopapillary neoplasm of the pancreas

The differential diagnosis of solid pseudopapillary neoplasm (SPN) from some other nonductal pancreatic tumors may be difficult because of similarities in morphological features. Therefore, immunohistochemical staining is frequently necessary. α-Methylacyl-CoA racemase (AMACR) is a diagnostically useful marker for prostatic cancer and papillary renal cell carcinoma. The aim of this study was to investigate AMACR as a new immunohistochemical marker to differentiate SPNs from other nonductal pancreatic tumors. We investigated immunohistochemical staining for AMACR in 26 SPNs, 21 pancreatic neuroendocrine tumors, and 7 acinar cell carcinomas. All cases of SPN showed granular cytoplasmic expression of AMACR, whereas all cases of pancreatic neuroendocrine tumors and acinar cell carcinomas were negative for this immunohistochemical marker. Hence, our findings demonstrate for the first time that AMACR is a useful immunohistochemical marker for the differential diagnosis of SPNs.

Prognostic value of CA 19-9, CEA, CRP, LDH and bilirubin levels in locally advanced and metastatic pancreatic cancer: results from a multicenter, pooled analysis of patients receiving palliative chemotherapy

PURPOSE

CA 19-9 is the only established tumor marker in pancreatic cancer (PC); the prognostic role of other serum markers like CEA, CRP, LDH or bilirubin has not yet been defined.

METHODS

We pooled pre-treatment data on CA 19-9, CEA, CRP, LDH and bilirubin levels from two German multicenter randomized phase II trials together with prospective patient data from one high-volume German Cancer Center. Marker levels were assessed locally before the start of palliative first-line therapy for advanced PC and serially during treatment (for CA 19-9 only). Clinical and biomarker data (overall 12 variables) were correlated with the efficacy endpoints time-to-progression (TTP) and overall survival (OS) by using uni- and multivariate Cox models.

RESULTS

Data from 291 patients were included in this pooled analysis; 253 patients (87 %) received treatment within prospective clinical trials. Median TTP in the study cohort was 5.1 months and median OS 9.0 months. In univariate analysis, pre-treatment CA 19-9 (HR 1.55), LDH (HR 2.04) and CEA (HR 1.89) levels were significantly associated with TTP. Regarding OS, baseline CA 19-9 (HR 1.46), LDH (HR 2.07), CRP (HR 1.69) and bilirubin (HR 1.62) were significant prognostic factors. Within multivariate analyses, pre-treatment log [CA 19-9] (as continuous variable for TTP) and log [bilirubin] as well as log [CRP] (for OS) had an independent prognostic value. A CA 19-9 decline of ≥25 % during the first two chemotherapy cycles was predictive for TTP and OS, independent of the applied CA 19-9 assay.

CONCLUSION

Baseline CA 19-9 and CA 19-9 kinetics during first-line chemotherapy are prognostic in advanced PC. Besides that finding other serum markers like CRP, LDH and bilirubin can also provide prognostic information on TTP and OS.

Acinic cell carcinoma of the salivary glands: an immunohistochemical study of angiogenesis in 12 cases

Acinic cell carcinoma (ACC) is the third most common epithelial malignancy of the salivary glands in adults, exhibiting a low-grade malignancy that mainly occurs in the parotid gland and at a relatively younger age than other salivary gland tumors. We performed an immunohistochemically study regarding angiogenesis in ACC, by assessing the CD105+ tumor microvessels density and investigating the VEGF and its receptors VEGFR1 and VEGFR2 expression in tumor samples. The results indicated an active angiogenesis in ACC, with the highest CD105-MVD score recorded in the solid variant. This fact was supported by the reactivity of tumor cells and endothelial blood vessel cells for VEGF and its receptors (VEGFR1 and VEGFR2). Thus, we concluded that in ACC do exist autocrine and paracrine VEGF loops implicated in growth and progression of this kind of salivary gland tumors.

[Pancreatic acinar cell adenoma]

The paper describes two cases of acinar cell adenoma, a rare tumor of the pancreas, diagnosed in two 70- and 58-year-old women after surgery. It presents a histological description of the tumor and the results of immunohistochemical tests performed.

[Lung carcinoma producing carbohydrate antigen 19-9; report of a case]

A 58-year-old female was admitted to our hospital for investigation of serum elevation of carbohydrate antigen (CA 19-9). Computed tomography of the chest revealed a spiculated pulmonary nodule with the longest diameter of 3.7 cm in the right lower lobe. The diagnosis of lung adenocarcinoma was made. The patient underwent right lower lobectomy with lymphnode dissection. Histological examination revealed acinar type adenocarcinoma. The tumor was classified as stage IB with T2aN0M0. Immunohistochemically, the tumor cells stained positively for CA19-9. The serum CA19-9 level returned to a normal level after operation, but increased again with mediastinal lymphnode metastasis and brain metastasis. She died after an operation in 16 months.

Reduced glycosylation of α-dystroglycans on carcinoma cells contributes to formation of highly infiltrative histological patterns in prostate cancer

BACKGROUND

α-Dystroglycan (DG) carries glycan chains that bind to laminin and thus function in homeostasis of not only skeletal muscle but also of various epithelial cells. Loss of glycosylation has been suggested to play important roles in tumor development, particularly in detachment and migration of carcinoma cells. We previously reported that glycosylation of α-DG, but not levels of α-DG core protein itself, is reduced in prostate carcinoma. In this study, we investigate the association between reduction of laminin-binding glycans on α-DG and the degree of tumor cell differentiation and/or infiltrative properties, as assessed by the Gleason grading system.

METHODS

Immunohistochemical analysis of 146 biopsy specimens of prostate adenocarcinoma with various Gleason scores was carried out employing IIH6 and 6C1 antibodies, which recognize laminin-binding glycans on α-DG and α-DG core proteins, respectively. Double immunofluorescence staining was performed to evaluate colocalization of α-DG and laminin, and to determine which types of epithelial cells express laminin-binding glycans on α-DG.

RESULTS

Reduction of α-DG glycosylation, rather than loss of α-DG core protein, was correlated with higher Gleason patterns. Reduction was most conspicuous at the interface between carcinoma cells and the basement membrane. In addition, in non-neoplastic prostate glands, laminin-binding glycans were expressed predominantly on the basolateral surface of basal cells.

CONCLUSIONS

Reduced expression of laminin-binding glycans on α-DG may contribute to formation of highly infiltrative behavior of prostate carcinoma cells. Substantial reduction of laminin-binding glycans in carcinoma tissue could be partly ascribed to disappearance of pre-existing basal cells.

Immunohistochemical evaluation of solid pseudopapillary tumors of the pancreas: the expression pattern of CD99 is highly unique

The aim of this study was to investigate CD99 as a new marker to characterize solid pseudopapillary tumors (SPTs), and to determine a specific panel of markers to identify the disease. We analyzed the clinicopathological characteristics and immunohistochemical features of 37 patients with SPT. All 37 tumors displayed intracytoplasmic dot-like immunoreactivity of CD99 in contrast to membranous staining in all pancreatic endocrine tumors and most of acinar cell carcinomas, along with negative immunostaining in ductal carcinomas. In addition, we observed a loss of expression of E-cadherin in all SPTs as well as in some other pancreatic tumors, and aberrant nuclear expression of β-catenin in most SPTs. Our findings demonstrated for the first time that the pattern of CD99 expression was highly specific for distinguishing SPTs from other pancreatic tumors. CD99 combined with E-cadherin/β-catenin and CD10 can be used as a relatively specific expression profile of SPTs.

E-cadherin and β-catenin expression in canine colorectal adenocarcinoma

E-cadherin and its associated cytoplasmic proteins, including β-catenin, have been examined as potential oncogenic markers due to the significant correlation between tumour dedifferentiation and the invasive capacity of epithelial tumours. The purpose of this study was to evaluate the expression of E-cadherin and β-catenin in canine colorectal cancer using immunohistochemistry and to examine the relationship between this expression and various clinicopathological variables. The expression pattern of E-cadherin and β-catenin was investigated in 44 colorectal canine carcinomas. In the intestinal mucosa of noncancerous areas, epithelial cells demonstrated equally strong membranous expression of E-cadherin and β-catenin localised to the cell-cell junctions. Reduced expression of E-cadherin and β-catenin was demonstrated in 75% and 81.8% of the colorectal carcinoma cases, respectively. The down-regulation of both E-cadherin and β-catenin was correlated with decreased differentiation and increased tumour grade. In addition, the expression of β-catenin was correlated with tumour size. These results suggest that dysfunction of the E-cadherin-catenin complex starts in the early stages of carcinogenesis and that the disruption of the tissue architecture is progressively associated with the invasion of the tumour.

Matrix metalloproteinase (MMP)-7 in salivary gland cancer

INTRODUCTION

High levels of certain matrix metalloproteinases (MMPs) have been detected in various human cancers. The purpose of this study was to analyze the expression of MMP-7 in salivary gland cancer (SGC) by immunohistochemistry and to associate the results with the clinical data and the 10-year survival of the SGC patients.

MATERIAL AND METHODS

Immunohistochemistry for MMP-7 was performed in a series of 107 paraffin-embedded sections of SGC. The samples represent the entire SGC population in Finland from 1991-1996. Mortality follow-up ended December 31, 2006.

RESULTS

The study population of 107 patients consisted of 47 male and 60 female subjects, ranging in age at the time of diagnosis between 23 and 90 years. The minimum follow-up time was 10.6 years and the maximum 15.9 years. By age-adjusted analysis lower staining intensity was associated with worse overall survival of patients with acinic cell carcinoma (p = 0.047, HR 6.5, 95% Cl 1.0-41.7) and in mucoepidermoid carcinoma (p = 0.010, HR 9.3, 95% CI 1.7-50.0). Low staining intensity was also associated with worse disease-specific survival of patients with acinic cell carcinoma (0-1 vs. 2-3; p = 0.047, HR 13.7, 1.0-200.0). VCI Ki-67 was an important prognostic factor for survival of the entire data set (p < 0.0001, HR 4.7, 95% Cl 2.3-9.8).

CONCLUSIONS

MMP-7 is associated with the prognosis of patients with acinic cell and mucoepidermoid carcinoma.

Detection of pancreatic carcinomas by imaging lactose-binding protein expression in peritumoral pancreas using [18F]fluoroethyl-deoxylactose PET/CT

Background

Early diagnosis of pancreatic carcinoma with highly sensitive diagnostic imaging methods could save lives of many thousands of patients, because early detection increases resectability and survival rates. Current non-invasive diagnostic imaging techniques have inadequate resolution and sensitivity for detection of small size (∼2–3 mm) early pancreatic carcinoma lesions. Therefore, we have assessed the efficacy of positron emission tomography and computer tomography (PET/CT) imaging with β-O-D-galactopyranosyl-(1,4′)-2′-deoxy-2′-[¹⁸F]fluoroethyl-D-glucopyranose ([¹⁸F]FEDL) for detection of less than 3 mm orthotopic xenografts of L3.6pl pancreatic carcinomas in mice. [¹⁸F]FEDL is a novel radioligand of hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), which is overexpressed in peritumoral pancreatic acinar cells.

Methodology/Principal Findings

Dynamic PET/CT imaging demonstrated rapid accumulation of [¹⁸F]FEDL in peritumoral pancreatic tissue (4.04±2.06%ID/g), bi-exponential blood clearance with half-lives of 1.65±0.50 min and 14.14±3.60 min, and rapid elimination from other organs and tissues, predominantly by renal clearance. Using model-independent graphical analysis of dynamic PET data, the average distribution volume ratio (DVR) for [¹⁸F]FEDL in peritumoral pancreatic tissue was estimated as 3.57±0.60 and 0.94±0.72 in sham-operated control pancreas. Comparative analysis of quantitative autoradiographic images and densitometry of immunohistochemically stained and co-registered adjacent tissue sections demonstrated a strong linear correlation between the magnitude of [¹⁸F]FEDL binding and HIP/PAP expression in corresponding regions (r = 0.88). The in situ analysis demonstrated that at least a 2–4 fold apparent lesion size amplification was achieved for submillimeter tumors and to nearly half a murine pancreas for tumors larger than 3 mm.

Conclusion/Significance

We have demonstrated the feasibility of detection of early pancreatic tumors by non-invasive imaging with [¹⁸F]FEDL PET/CT of tumor biomarker HIP/PAP over-expressed in peritumoral pancreatic tissue. Non-invasive non-invasive detection of early pancreatic carcinomas with [¹⁸F]FEDL PET/CT imaging should aid the guidance of biopsies and additional imaging procedures, facilitate the resectability and improve the overall prognosis.

Activation of PyMT in beta cells induces irreversible hyperplasia, but oncogene-dependent acinar cell carcinomas when activated in pancreatic progenitors

It is unclear whether the cellular origin of various forms of pancreatic cancer involves transformation or transdifferentiation of different target cells or whether tumors arise from common precursors, with tumor types determined by the specific genetic alterations. Previous studies suggested that pancreatic ductal carcinomas might be induced by polyoma middle T antigen (PyMT) expressed in non-ductal cells. To ask whether PyMT transforms and transdifferentiates endocrine cells toward exocrine tumor phenotypes, we generated transgenic mice that carry tetracycline-inducible PyMT and a linked luciferase reporter. Induction of PyMT in β cells causes β-cell hyperplastic lesions that do not progress to malignant neoplasms. When PyMT is de-induced, β cell proliferation and growth cease; however, regression does not occur, suggesting that continued production of PyMT is not required to maintain the viable expanded β cell population. In contrast, induction of PyMT in early pancreatic progenitor cells under the control of Pdx1 produces acinar cell carcinomas and β-cell hyperplasia. The survival of acinar tumor cells is dependent on continued expression of PyMT. Our findings indicate that PyMT can induce exocrine tumors from pancreatic progenitor cells, but cells in the β cell lineage are not transdifferentiated toward exocrine cell types by PyMT; instead, they undergo oncogene-dependent hyperplastic growth, but do not require PyMT for survival.

A spontaneous acinar cell carcinoma model for monitoring progression of pancreatic lesions and response to treatment through noninvasive bioluminescence imaging

PURPOSE

We have generated an EL1-luc/TAg transgenic mouse model that develops spontaneous and bioluminescent acinar cell carcinomas. We applied this model to noninvasively monitor tumor development and drug response.

EXPERIMENTAL DESIGN

EL1-luc/TAg transgenic mice of 11 weeks of age were treated with rapamycin (5 mg/kg, i.p.) or vehicle for 6 to 12 weeks. Tumor development was monitored through bioluminescence imaging and necropsy at the study end point.

RESULTS

EL1-luc/TAg transgenic mice showed pancreas-specific bioluminescence signal before tumor progression and produced increasing light emission from the onset of the pancreatic acinar cell carcinomas. The latency of tumor development ranged from 10 to >20 weeks of age in these mice. Progression of the primary acinar cell carcinoma was accompanied by emergence of metastatic lesions in the abdominal organs, including liver and gastrointestinal fat tissues. Rapamycin treatment suppressed tumor development.

CONCLUSIONS

The EL1-luc/TAg mouse provides a noninvasive approach for monitoring spontaneous acinar cell carcinoma development and comprises a convenient tool for the evaluation of novel therapeutics against pancreatic cancers. Tumor growth suppression through inhibition of the mammalian target of rapamycin pathway further validates this model as clinically relevant.

Primary acinar cell carcinoma of the liver

We report a case of acinar cell carcinoma primary to the liver. The tumor was diagnosed in a 35-year-old woman complaining of abdominal pain and asthenia; serum alpha-fetoprotein (AFP) levels were increased at 6,000 IU/mL; imaging studies showed a hypervascular mass located in the left lobe of the liver. A left lobectomy was performed. The tumor had a heterogeneous appearance. In well-differentiated areas, tumor cells formed acinar structures, had a pyramidal shape and a highly eosinophilic, granular cytoplasm, PAS diastase resistant. In less-differentiated areas, tumor cells were endocrinelike. The immunohistochemical study showed that tumor cells expressed trypsin. Alpha-fetoprotein and alphal-antritrypsin were detected in about 30% of cells; HepPar1 was present in 15% of cells. Chromogranin A and synaptophysin were detected in rare cells. After surgery, serum AFP levels quickly returned to normal; no evidence of recurrence or metastasis was observed during follow-up. The final diagnosis, based on histological, immunohistochemical, and ultrastructural arguments, was extra-pancreatic acinar cell carcinoma, primary to the liver. This unusual lesion is likely to be the result of an abnormal differentiation pathway involving a transformed multipotential progenitor cell.

[Pathologic characteristics of pseudohyperplastic prostatic adenocarcinoma]

OBJECTIVE

To study the clinicopathologic features of 30 cases of pseudohyperplastic prostatic adenocarcinoma (PHPA).

METHODS

Eight hundred and sixty cases of ultrasound-guided prostatic needle biopsy and 46 cases of radical prostatectomy specimens collected during the period from January 1, 2005 to December 31, 2006 were retrieved from the archival files. The incidence, morphology, pathologic differential diagnosis, tumor volume, preferred location and Gleason's score were studied. The tissue sections suspicious for PHPA were immunohistochemically stained with high-molecular weight cytokeratin (34betaE12) or CK5/6, p63, AMACR, and cocktail antibody of 34betaE12/p63/AMACR. Cases with PHPA component more than 60% in at least one single slide were selected and pathologically analyzed.

RESULTS

PHPA was present in 7% of needle biopsy and 15.2% of prostatectomy specimens. Histologically, 66.7% of PHPA demonstrated direct transition with conventional acinar adenocarcinoma; and 76.7% of cases had coexisting conventional acinar adenocarcinoma in the remaining tissue blocks. The tumor volume accounted for 5% to 100% of total carcinoma among core needle biopsy and 1% to 30% of total carcinoma among radical prostatectomy. PHPA resembled benign prostate glands, in which the hyperplastic malignant acini were predominantly of medium to large size. The neoplastic cells were well-differentiated, with basally located nuclei and luminal corpora amylacea. However, amongst the 20 pathologic indices of prostatic malignancy studied, occurrence of 10 or more indices exceeded 66.7%. Although PHPA looked benign morphologically, 66.7% cases had stromal invasion, 6.7% had perineural invasion and 3.3% had bone metastasis. The tumor was primarily located in the peripheral zone.

CONCLUSIONS

PHPA is not a rare phenomenon in prostatic adenocarcinoma. Majority of cases have concurrent conventional acinar adenocarcinoma. It is different from well-differentiated (with Gleason's score 1 or 2) adenocarcinoma with a relatively indolent clinical course. In contrast, PHPA corresponds to moderately differentiated adenocarcinoma with Gleason's score of 3.

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.

Pancreatic acinar cell carcinoma with excessive alpha-fetoprotein expression

We report a case of acinar cell carcinoma of the pancreas associated with excessively elevated levels of serum alpha-fetoprotein (>32,000 ng/ml). Abdominal computed tomography scan revealed a large pancreatic mass with infiltration of the splenic artery. Because of inoperability, palliative combination chemotherapy with gemcitabine and mitomycin C was administered. This regimen was associated with clinical improvement and dramatic decreases in both tumor size and serum alpha-fetoprotein. However, the patient died 7 months later from acute severe cardiac failure.

Alpha-fetoprotein-producing Pancreatic Acinar Cell Carcinoma

A 47-year-old man with chronic hepatitis B had progressive elevated alpha-fetoprotein of 2 years' duration. A pancreatic tail tumor, instead of liver tumor, was detected. He underwent elective distal pancreatectomy and splenectomy and the pathology turned out to be acinar cell carcinoma of the pancreas. Serum level of alpha-fetoprotein returned to normal soon after surgery. No cancer recurrence was noted after 3 years of follow-up. Alpha-fetoprotein is commonly used as a tumor marker to screen for hepatocellular carcinoma in high-risk patients. However, elevated alpha-fetoprotein could occur in a much rarer disease, acinar cell carcinoma of the pancreas.

Implications of methylation patterns of cancer genes in salivary gland tumors

PURPOSE

We investigated the methylation status and protein expression of four tumor suppressor genes to determine their role in salivary gland tumorigenesis.

EXPERIMENTAL DESIGN

We performed methylation-specific PCR and protein analyses of 29 normal salivary glands, 23 benign, and 79 malignant salivary gland neoplasms to determine the pattern and potential diagnostic and/or biological role of the RASSF1, RARbeta2, DAPK, and MGMT tumor suppressor gene methylation in these tumors.

RESULTS

No methylation was detected in the normal tissues. Methylation occurred in 9 of 23 (39.1%) benign tumors; 3 (25.0%) pleomorphic adenomas and 6 (66.7%) Warthin's tumors at the MGMT, DAPK, or RASSF1 genes. Methylation occurred in 33 of 79 (41.8%) malignant tumors; 8 (30.8%) adenoid cystic carcinomas, 6 (33.3%) mucoepidermoid carcinomas, 6 (42.9%) acinic cell carcinomas, and 13 (62.0%) salivary duct carcinomas. RASSF1 and RARbeta2 represented 75.8% of methylation events occurring most frequently in salivary duct and acinic cell carcinomas. Overall, we found no significant correlation between protein expression and methylation status of individual genes, but observed low or absent protein expression in several methylated tumors. Significant correlations were found between methylation and aggressive malignant phenotypes (P = 0.0004) and age (P = 0.05).

CONCLUSIONS

(a) Benign and malignant salivary tumors differed in the frequency and pattern of gene methylation; (b) high-grade carcinomas were significantly methylated compared with low-grade phenotypes; (c) RASSF1 and RARbeta2 were highly methylated in malignant tumors and can be targeted for therapy; and (d) methylation pattern may serve as a diagnostic and biological marker in assessing these tumors.

Pure acinic cell carcinoma of the breast in an 80-year-old Japanese woman

Acinic cell carcinoma of the breast is an uncommon neoplasm. Since the first case of this rare variant of breast carcinoma was reported in 1996, only 10 cases have been reported in the English-language literature. Reported herein is the first case of primary acinic cell carcinoma of the breast in a Japanese woman. To the naked eye, the tumor appeared well circumscribed and the cut surface was grayish-pink and hemorrhaging. Microscopically, the tumor was predominantly made up of a monotonous proliferation of cells with a finely granular cytoplasm, resembling acinic cells of the parotid gland. Some neoplastic cells had a clear cytoplasm. In spite of extensive sampling, no common histological patterns of breast carcinoma such as in situ and invasive ductal carcinoma were recognized in the present case, indicating that the present case was pure acinic cell carcinoma. In addition, the immunohistochemical profile of this tumor was identical to that of the acinic cell carcinoma of the salivary gland: estrogen receptor, progesterone receptor, HER2 and cytokeratin (CK)20 were negative and amylase and CK7 were positive. The patient has been well for 22 months since the wide local excision of the tumor and no signs of salivary neoplasm are evident to date.

Pancreatic endocrine tumor with partial acinar cell differentiation

We examined a 70-year-old woman in whom a pancreatic endocrine tumor with partial acinar cell differentiation had been diagnosed. She had neither endocrine nor exocrine symptoms. The tumor was located in the pancreatic tail and measured 12.5 x 9.5 x 8 cm. It had a capsule, was composed of multiple adhesion nodules, and was elastically soft, medullary, and yellowish white. The neoplastic cells had large, irregular, oval nuclei; prominent eosinophilic nucleoli; and abundant eosinophilic cytoplasm with many fine granules. The cells had proliferated in islet-like solid medullary, trabecular, acinar, and papillary patterns. Most neoplastic cells were strongly positive for synaptophysin. 10 to 25% of the neoplastic cells were positive for alpha1-antitrypsin. Neuroendocrine and zymogen granules were simultaneously observed in the cytoplasm of the same neoplastic cells at the ultrastructural level. The tumor may be considered an amphicrine tumor.

Iressa induces cytostasis and augments Fas-mediated apoptosis in acinic cell adenocarcinoma overexpressing HER2/neu

Understanding the role of signal transduction in regulating pathways responsible for cell growth, survival and apoptosis is critical for cancer therapy. We developed and characterized a HER2/neu and Fas overexpressing cell line (BNT.888 ACA2) from a salivary gland adenocarcinoma that arose in a HER2/neu transgenic mouse. We evaluated the effects of Iressa on signal transduction networks downstream of the activated HER2 and the impact on proliferation, cell cycle and apoptosis. Iressa treatment diminished phosphorylation of the HER2/neu and EGFR. Phosphorylation of STAT-3 also decreased and mitogenic signaling through the MAPK pathways was greatly reduced. Cyclin D1 levels decreased, and cells were arrested in G0 and failed to enter S-phase because of hypophosphorylation of Rb and to traverse the G2M checkpoint because of degradation of cyclin B1. Cytostasis occurred within 48 hr at 250-500 nM Iressa. Levels of proapoptotic factors (bim and bax) increased and levels of antiapoptotic factors (bcl-2 and bcl-xL) decreased in a dose-dependent manner. Higher doses of Iressa diminished phosphorylation of Akt slightly, but failed to induce apoptosis. Fas antibody was a potent agonist of apoptosis. Pretreatment with Iressa (1 microM, 24 hr) greatly enhanced Fas-mediated apoptosis as determined by Annexin V binding, cleavage of caspase-3 and PARP. Augmentation of apoptosis was associated with increased Fas expression and membrane localization. Iressa pretreatment increased bid activation, cleavage of caspases -3, -9 and -12 and stress signaling via c Jun. These data showing that Iressa induces cytostasis and primes the extrinsic (Fas) and intrinsic (mitochondrial and endoplasmic reticulum) apoptotic pathways should lead to the development of novel therapeutic targets and strategies.

Unique case of pulmonary bronchial gland type tumor with broad spectrum of cell differentiation from the terminal duct-acinar unit to excretory duct

In the lung, acinic cell carcinoma (ACC) is a rare form of tumor. Reported herein is a unique bronchial gland-type tumor diagnosed as well-differentiated ACC that developed in the B9 bronchus of the left lung. Various immunohistochemical and histochemical staining partly satisfied the diagnosis of ACC. Moreover, this tumor contained various sizes of mucous cysts lined by columnar mucous cells, which produced abundant mucin positive for Alcian blue, which is usually present in mucoepidermoid carcinoma. Therefore, the present case is a unique tumor having a broad spectrum of cell differentiation from the terminal duct--acinar unit to the striated duct and excretory duct. This is the first case of unique bronchial gland-type tumor with mixed histological features of ACC and mucoepidermoid carcinoma.

Correlation of human Bub1 expression with tumor-proliferating activity in salivary gland tumors

Human Bub1 plays an important role at the spindle assembly check-point to prevent cell cycle progression following spindle damage. We examined the expression of Bub1 mRNA and protein in 21 human salivary gland tumors (7 pleomorphic adenomas, 2 warthin tumors, 5 mucoepidermoid carcinomas, 3 adenoid cystic carcinomas and 4 acinic cell carcinomas) and 3 normal submandibular glands using real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) or western blotting. The mean expression levels of Bub1 mRNA and protein were higher in malignant tumors (0.12+/-0.028/1.75+/-0.53) than normal submandibular glands (0.042+/-0.014/0.19+/-0.044) and benign tumors (0.058+/-0.01/0.97+/-0.44). We found a significant association between the level of Bub1 mRNA/protein expression and clinical stage in malignant tumors (Mann-Whitney U test, p=0.019/p=0.016). We analyzed its relation with the proliferative activity monitored by the Ki-67 labeling index by immunohistochemistry as well as the expression of proliferating cell nuclear antigen (PCNA) by Western blotting. A significant correlation was found between Bub1 mRNA/protein expression and the Ki-67 labeling index in salivary gland tumors (Spearman's correlation coefficient by rank test, p=0.026/p=0.002). These results indicate that increased expression of the human Bub1 gene is closely linked to abnormal cell proliferation in malignant conditions.