Salivary duct carcinoma--a highly aggressive salivary gland tumor with HER-2/neu oncoprotein overexpression

Differential expression of TRKB tyrosine kinase in the two histological types of parotid salivary duct carcinoma with cancer aggressiveness

Parotid salivary duct carcinoma (SDC) is a rare and aggressive parotid gland carcinoma (PGC). SDC has two origins: de novo and ex pleomorphic adenoma (SDC ex PA); however, because of its rarity, the clinical and molecular features of the two types of SDC are not sufficiently understood. Here, we studied the differences in their clinicopathological and molecular features using clinical specimens while comparing them to those of adenoid cystic carcinoma (AdCC), an intermediate-grade PGC. Clinicopathological analysis of tissues from patients with PGC revealed significant associations between histological types and malignant phenotypes, including nodal metastasis, recurrence, vascular invasion, and neural invasion, and revealed more malignant phenotypes of de novo SDC than of SDC ex PA. The de novo SDC showed a significantly higher frequency of intra-neural invasion (intra-NI) and vascular invasion than AdCC and SDC ex PA. PGCs with high intra-NI were significantly correlated with malignant phenotypes and survival rates. Recently, we observed the overexpression of tropomyosin receptor kinase B (TRKB), a receptor tyrosine kinase, in PGC cells. Here, immunohistochemical and clinicopathological analyses showed that TRKB was highly expressed in SDC cells, particularly de novo SDC cells, and was significantly associated with poor survival and highly malignant phenotypes, including intra-NI and vascular invasion. Collectively, these data show that TRKB expression is significantly elevated in PGC, particularly in de novo SDC, and can be one of the biomarkers of their aggressiveness.

ERBB2 amplification status in 67 salivary duct carcinomas assessed by immunohistochemistry, fluorescence in situ hybridization, and targeted exome sequencing

Salivary duct carcinoma (SDC) is an aggressive salivary gland malignancy with poor survival. Approximately 30% SDC harbor HER2 amplification and response to trastuzumab has been reported. However, a systematic approach for HER2 status assessment in this tumor type has not been established. A total of 67 tumor samples were evaluated for HER2 protein overexpression or ERBB2 gene amplification using at least 2 methods: immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and/or targeted exome next-generation sequencing (NGS). NGS assessed ERBB2 copy number fold change (FC) and total copy number (TCN). HER2 status was first determined by IHC/FISH according to the 2018 ASCO/CAP breast cancer guidelines. FISH results, the "gold standard", were compared with the NGS results. All (15/15) IHC positive, 35% (6/17) equivocal, and no (0/19) IHC negative SDC were HER2 amplified by FISH. HER2 FISH signal/cell showed a good correlation with FC (Spearman correlation: 0.708, R²: 0.501, p < 0.0001) and TCN (Spearman correlation: 0.763, R²: 0.582, p < 0.0001). Receiver operating characteristics curve estimation showed an area under curve (AUC) of 0.975 for ERBB2 FC. FC cutoff of ≥1.8 corresponded to an accuracy of 95.2% for ERBB2 amplification (Youden's index: 0.84, sensitivity: 89.47%, specificity: 100%). FC < 1.3 could be reliably classified as ERBB2 not amplified and FC ≥ 1.3 and <1.8 as equivocal. TCN estimation showed AUC of 0.981. TCN cutoff of >6.0 corresponded to an accuracy of 92% for HER2 amplification (Youden's index: 0.81, sensitivity: 81.2%, specificity: 100%). TCN < 4 could be reliably classified as ERBB2 not amplified and TCN ≥ 4.0 and ≤6.0 as equivocal. FC and TCN were binarized with respective cutoffs of ≥1.8 and ≥6.0 and the proportion of agreement with FISH were 95% and 92%, respectively. The assessment of ERBB2 copy number by NGS is accurate and reliable with FC or TCN nearly equivalent to FISH in identifying HER2 amplified SDC.

HER2 Positivity in Histological Subtypes of Salivary Gland Carcinoma: A Systematic Review and Meta-Analysis

Background

HER2 aberrations in salivary gland carcinomas (SGC) as well as benefit of HER2 directed therapy have been reported in small studies. However, reliable estimates of the prevalence of HER2 positivity in SGC and its various histological subtypes are lacking.

Objective

To assess the prevalence of HER2 positivity in histological subtypes of salivary gland carcinomas (SGC).

Methods

Studies were identified by a systematic review of the literature. Data on in situ hybridization (ISH) and immunohistochemistry (IHC) were extracted to derive pooled prevalence estimates calculated by a random effects model. Characteristics of the studies were extracted for subgroup analysis.

Results

Fifty studies including 3372 patients were identified, providing data on sixteen histological subtypes. Based on the meta-analysis, the estimated prevalence of HER2 positivity were 43% (95% CI: 36% – 51%) in salivary duct carcinoma (SDC), 39% (95% CI: 32% – 45%) in carcinoma ex pleomorphic adenoma (CEP), 17% (95% CI: 7.5% – 33%) in squamous cell carcinoma (SCC), 13% (95% CI: 7.6% – 21%) in adenocarcinoma NOS (ADC), 6.7% (95% CI: 0.17%-32%) in poorly differentiated carcinoma, 5.5% (95% CI: 2.9% – 9.6%) in mucoepidermoid carcinoma, 4.3% (95% CI: 1.4% – 13%) in myoepithelial carcinoma, 1.8% (95% CI: 0.04%-9.6%) in epithelial-myoepithelial carcinoma, 0.45% (95% CI: 0.0097% – 18%) in acinic cell carcinoma and 0.15% (0.037% – 5.4%) in adenoid cystic carcinoma. Estimates for five additional subtypes were assessed.

Conclusion

Prevalence of HER 2 positivity in SGC varies greatly based on histological subtype, with SDC, CEP, SCC, and ADC displaying the highest rates.

Anticancer Effects of Sublingual Type I IFN in Combination with Chemotherapy in Implantable and Spontaneous Tumor Models

Salivary gland tumors are a heterogeneous group of neoplasms representing less than 10% of all head and neck tumors. Among salivary gland tumors, salivary duct carcinoma (SDC) is a rare, but highly aggressive malignant tumor resembling ductal breast carcinoma. Sublingual treatments are promising for SDC due to the induction of both local and systemic biological effects and to reduced systemic toxicity compared to other administration routes. In the present study, we first established that the sublingual administration of type I IFN (IFN-I) is safe and feasible, and exerts antitumor effects both as monotherapy and in combination with chemotherapy in transplantable tumor models, i.e., B16-OVA melanoma and EG.7-OVA lymphoma. Subsequently, we proved that sublingual IFN-I in combination with cyclophosphamide (CTX) induces a long-lasting reduction of tumor mass in NeuT transgenic mice that spontaneously develop SDC. Most importantly, tumor shrinkage in NeuT transgenic micewas accompanied by the emergence of tumor-specific cellular immune responses both in the blood and in the tumor tissue. Altogether, these results provide evidence that sublingual IFN holds promise in combination with chemotherapy for the treatment of cancer.

Genomic Analysis of Salivary Gland Cancer and Treatment of Salivary Gland Cancers

Salivary gland cancer is a heterogenous group of tumors that presents challenges with both diagnosis and therapy. Recent advances in the classification of salivary gland cancers have led to distinct histologic and genomic criteria that successfully differentiate between cancers with similar clinical behavior and appearance. Genomic abnormalities have led to the emergence of targeted therapies being used in their therapy with drastic improvements in outcomes as well as reductions in treatment-related toxicity. Dramatic results seen with molecular targets, such as HER2, TRK, and others, indicate that this approach has the potential to yield even better treatments for the future.

Estrogen Receptor, Progesterone Receptor, and HER-2 Expression in Recurrent Pleomorphic Adenoma

Pleomorphic adenoma (PA) is the most common salivary gland neoplasm and, although mostly benign, recurrences, being called recurrent pleomorphic adenoma (RPA) and malignant transformation to carcinoma ex pleomorphic adenoma (CXPA), do occur. Recently, attention has been focused on molecular targeted cancer therapy in various tumors, including salivary gland tumors. The aim of this study was to investigate the role of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) in PA, RPA, and CXPA. In total, 20 cases of PA, 18 of RPA, and 7 cases of CXPA were immunohistochemically studied for ER, PR, and HER-2. For evaluation of ER and PR, only nuclear expression and greater than 10% positive cells were regarded as cutoff criteria. HER-2 was evaluated semiquantitatively and graded from 0 to 3+. HER-2 amplification was assessed by chromogenic in situ hybridization (CISH). Tumors were negative for ER, PR, and HER-2 in all cases of PA and RPA. A case of CXPA showed moderate and complete membranous staining, and 6 cases were negative. HER-2 amplification was not observed in any case. In conclusion, the lack of ER, PR, and HER-2 expression in PA, RPA, and CXPA suggests that these proteins are not involved in progression, recurrence, or malignant transformation of PA.

Targeted therapy with trastuzumab for epidermal growth factor receptor 2 (HER2)-positive advanced salivary duct carcinoma: A case report

Herein we report two cases of advanced and/or metastatic salivary duct carcinoma that relapsed after standard first-line chemotherapy. As overexpression of human epidermal growth factor receptor 2 (HER2) (3+) was observed by immunohistochemistry, the patients were treated with trastuzumab plus paclitaxel. One patient showed a complete response lasting over 2.5 years after the commencement of therapy; however, the other patient had no response to trastuzumab combined therapy. Dual fluorescence in situ hybridization was performed after the initiation of chemotherapy; the first case was positive for HER2 gene amplification, while the second case was negative. Our experiences suggest that therapy with HER2 blockers should be considered as options for treatment of HER2-positive salivary duct carcinoma. However, HER2 protein overexpression and gene amplification should be investigated further as therapeutic biomarkers.

Parotid salivary duct carcinoma: a single institution's 20-year experience

Purpose

The aim of the study was to assess the treatment results of the parotid gland salivary duct carcinoma (SDC).

Material and methods

A retrospective clinicopathological analysis of 40 patients treated for parotid SDC in 1996–2015 was performed. The impact of following factors on 5-year disease-free survival (DFS) and overall survival (OS) was studied: age, sex, preoperative 7th nerve palsy, skin infiltration, pT, pN, surgical margin, type of parotidectomy and neck dissection, histology (SDC de novo vs. SDC ex pleomorphic adenoma, SDCexPA), intra/periparotid lymph nodes metastases, perineural invasion (PNI), extraparenchymal extension (EPE), and overexpression HER2.

Results

The average age of the patients was 62 years (ranged from 39 to 81). Males predominated (57.5%). Patients with the clinical stage IV predominated (82.5%). In 1/3 of patients preoperative, 7th nerve palsy occurred. All patients were treated surgically, and all but one had supplementary radiotherapy. In 28 patients (70%), total radical parotidectomy was performed. A neck dissection was performed in all patients. In 19 cases (47.5%), SDCexPA was diagnosed. Negative microscopic surgical margin was obtained in 60% of patients. The follow-up for the whole analyzed group ranged from 2 to 22 years, average was 11.6 years. In 23 patients (57.5%), the disease recurred. Local recurrence was observed in 10 (25%) and distant metastases in 15 (37.5%) cases. 20 patients (50%) died of cancer. 5-year DSF and OS were 42.5% and 41%, respectively. Univariate analysis proved that the significant influence on the survival had 7th nerve palsy (p = 0.024 and p = 0.017, respectively), higher pT-stage (p < 0.001), radical parotidectomy (p = 0.024 and p = 0.022), radical treatment of the neck (p = 0.001 and p = 0.002), EPE (p = 0.040 and p = 0.028), and histology SDCexPA and PNI (p = 0.036 and 0.048). Multivariate analysis showed that independent prognostic factors were the 7th nerve palsy and the histology SDCexPA, which worsened 5-year DFS, respectively, 3.61 and 3.94 times (p = 0.033 and p = 0.026). On the other hand, on 5-year OS, only 7th nerve palsy had an influence (3.86 times worse prognosis, p = 0.033).

Conclusions

SDC is a clinically aggressive cancer with high risk of local recurrence and distant metastases, however, with a chance of curing of around 40%. In the majority of patients, a radical surgical treatment is necessary due to the high clinical stage of disease. Worse prognosis have patients with preoperative 7th nerve palsy and in whom SDC develops in pleomorphic adenoma.

Salivary duct carcinoma: evaluation of treatment and outcome in a tertiary referral institute

PURPOSE

The aggressive behavior of salivary duct carcinoma (SDC) necessitates an aggressive treatment strategy, including surgery and radiotherapy (RT). We evaluated practice patterns and treatment outcomes in patients with SDC treated in our Institute.

METHODS

Patients with SDC of the parotid or submandibular gland treated with curative intention in our Institute from 1998 until 2016 were reviewed. Our diagnostic workup and treatment strategy were evaluated together with treatment outcomes.

RESULTS

Fifteen patients with SDC were included. Staging included MRI and ultrasound-guided fine needle aspiration cytology. Only in a minority (20%) of patients, the preoperative diagnosis of SDC was raised due to positive immunohistochemical staining for the androgen receptor (AR) on cytology. All patients were treated with (sub)total resection of the salivary gland and 53% underwent a therapeutic neck dissection. All patients except one received postoperative RT. Immunohistochemical staining was found positive for AR (100%) and human epidermal growth factor receptor 2 (HER2/neu) (13%). No local recurrences occurred. Regional and distant failure rates were 20% and 40%, respectively.

CONCLUSIONS

Excellent local control rates can be achieved with extensive (local) surgical treatment and postoperative RT. In case of lymph node metastases, a neck dissection with adjuvant postoperative RT is warranted. In patients with node-negative disease, a less aggressive approach for the neck seems feasible to reduce treatment-related morbidity.

The localization of pre mRNA splicing factor PRPF38B is a novel prognostic biomarker that may predict survival benefit of trastuzumab in patients with breast cancer overexpressing HER2

Cancer biomarkers that can define disease status and provide a prognostic insight are essential for the effective management of patients with breast cancer (BC).

The prevalence, clinicopathological and prognostic significance of PRPF38B expression in a consecutive series of 1650 patients with primary invasive breast carcinoma were examined using immunohistochemistry. Furthermore, the relationship(s) between clinical outcome and PRPF38B expression was explored in 627 patients with ER-negative (oestrogen receptor) disease, and 322 patients with HER2-overexpressing disease.

Membranous expression of PRPF38B was observed in 148/1388 (10.7%) cases and was significantly associated with aggressive clinicopathological features, including high grade, high mitotic index, pleomorphism, invasive ductal carcinoma of no specific type (IDC-NST), ER-negative, HER2-overexpression and p53 mutational status (all p < 0.01). In patients with ER-negative disease receiving chemotherapy, nuclear expression of PRPF38B was significantly associated with a reduced risk of relapse (p = 0.0004), whereas membranous PRPF38B expression was significantly associated with increased risk of relapse (p = 0.004; respectively) at a 5 year follow-up. When patients were stratified according to ER-negative/HER2-positive status, membranous PRPF38B expression was associated with a higher risk of relapse in those patients that did not receive trastuzumab therapy (p = 0.02), whereas in those patients with ER-negative/HER2-positive disease that received trastuzumab adjuvant therapy, membranous PRPF38B expression associated with a lower risk of relapse (p = 0.00018).

Nuclear expression of PRPF38B is a good prognostic indicator in both ER-negative patients and ER-negative/HER2-positive BC (breast cancer) patients, whereas membranous localisation of PRPF38B is a poor prognostic biomarker that predicts survival benefit from trastuzumab therapy in patients with ER-negative/HER2-overexpressing BC.

A 20-Year Review of 75 Cases of Salivary Duct Carcinoma

IMPORTANCE

Salivary duct carcinoma is a rare, aggressive malignancy of the salivary glands. Owing to its rare nature, clinical data are limited, and only a few clinical studies comprise more than 50 patients.

OBJECTIVE

To review the University of Pittsburgh Medical Center's experience with salivary duct carcinoma over a 20-year period, focusing on demographics, presentation, treatment, and outcome.

DESIGN, SETTING, AND PARTICIPANTS

This investigation was a retrospective cohort study in a multihospital institution with tertiary referral. A pathology database was reviewed for all cases of histopathologically diagnosed salivary duct carcinoma from January 1, 1995, to October 20, 2014. Patients who were referrals for pathology review only and were never seen at the institution were excluded. In total, 75 study patients were identified. The electronic medical record was reviewed for details regarding demographics, presentation, treatment, and outcome, including overall survival (OS) and disease-free survival (DFS). This study was supplemented with a review of the institution's Head and Neck Oncology Database for further clinical details.

MAIN OUTCOMES AND MEASURES

Primary outcome measures consisted of OS and DFS.

RESULTS

The study sample comprised 75 participants with a mean age at diagnosis of 66.0 years (age range, 33-93 years), and 29% (n = 22) were female. Most primary tumors were from the parotid gland (83%), with the next most frequent site being the submandibular gland (12%). Overall, 41% of the cases were carcinoma ex pleomorphic adenoma. Rates of other histologic features included the following: perineural invasion (69%), extracapsular spread (58%), ERBB2 (formerly HER2) positivity (31%) (62% of those who were tested), and vascular invasion (61%). The median OS was 3.1 years, and the median DFS was 2.7 years. Univariate Kaplan-Meier survival analyses demonstrated that facial nerve sacrifice and extracapsular spread were associated with lower OS (2.38 vs 5.11 years and 2.29 vs 6.56 years, respectively) and DFS (2.4 vs 3.88 years and 1.44 vs 4.5 years, respectively). Although underpowered, multivariable analysis demonstrated significantly worse OS in patients with N2 and N3 disease (hazard ratio [HR] 8.42, 95% CI, 1.84-38.5) but did not show significantly worse DFS or OS for facial nerve sacrifice or extracapsular spread. There was no association between ERBB2 positivity and survival and no difference in survival between patients receiving radiation therapy vs radiation therapy plus chemotherapy. No patients had recurrence or distant metastasis after 5 disease-free years.

CONCLUSIONS AND RELEVANCE

Salivary duct carcinoma is an aggressive disease. A large number of cases in this review were carcinoma ex pleomorphic adenoma and had classic negative prognostic indicators, such as perineural invasion, vascular invasion, and extracapsular spread. ERBB2 positivity was not associated with any difference in survival. Facial nerve involvement appears to indicate worse prognosis, as does nodal stage higher than N1. Recurrence and metastasis after 5 years are rare.

Denovo High Grade Salivary Duct Carcinoma: A Case Report and Review of Literature

Salivary Duct Carcinoma (SDC) is a distinctive and clinically aggressive adenocarcinoma of salivary origin. It arises from the ductal epithelium, predominantly occurring in the major salivary glands, especially the parotid gland. Here, we report a case of an extensive salivary gland pathology involving the right side of face, possibly arising from the parotid gland in a 25-year-old male patient. On routine histopathology, the tumour mass revealed a papillary pattern of neoplastic ductal epithelial cells showing comedo-like-central necrosis. Immunohistochemical staining showed tumour cells in the infiltrative component to be diffusely immunopositive for cytokeratin-7 and Her-2, confirming the diagnosis of SDC. This paper presents a case report on salivary duct carcinoma and highlights a review on histological variants of salivary duct carcinoma.

Lacrimal gland ductal carcinomas: Clinical, Morphological and Genetic characterization and implications for targeted treatment

PURPOSE

Ductal carcinomas (DCs) of the lacrimal gland are very rare but aggressive malignancies. We investigated DC of the lacrimal gland for potentially clinically actionable targets in the search for new therapeutic options.

METHODS

Case 1: A 77-year-old man, presented with diplopia and xerophtalmia; case 2: A 53-year-old man, presented with headache, proptosis and chemosis and case 3: A 73-year-old man, presenting with chemosis and a corneal abscess. All three cases were characterized morphologically including immunohistochemistry and genetically with fluorescence in situ hybridization (FISH) and one case with next-generation sequencing (NGS) of cancer relevant genes.

RESULTS

Cases 1 and 3 were composed of large, rounded, irregular cystic nodules of carcinoma cells with prominent central comedonecrosis, whereas case 2 had a scirrhous morphology. High expression of CK7, CK19, EMA, p53 and HER2 was characteristic for all three tumours. Androgen receptor was intensely positive in case 1, in scattered cells in case 2 and negative in case 3, whereas oestrogen and progesterone receptor were consistently negative. Genetically, a hemizygous deletion and a point mutation in PTEN were identified in case 1, whereas HER2 amplification was found in cases 2 and 3.

CONCLUSION

This study identified a spectrum of genetic events and pattern of protein expression in DC of the lacrimal gland similar to a subset of carcinomas of the breast and ductal carcinomas of the salivary glands. For therapeutic purposes, aberrations in several components of especially the HER2 signalling pathway could alleviate the effect of HER2-directed therapy illustrating an inadequacy of isolated HER2 testing.

Histological, immunohistological and molecular characteristics of intraductal precursor of carcinoma ex pleomorphic adenoma support a multistep carcinogenic process

In recent years, multistep carcinogenesis of carcinoma ex pleomorphic adenoma (CEPA) has been identified, starting with intraductal neoplasia within pre-existent pleomorphic adenoma (PA). However, as yet there is no consensus regarding clinical relevance and appropriate terminology of precursor lesions in CEPA. We therefore decided to investigate precursor lesions, especially intraductal carcinoma, in a series of 85 cases of CEPA. Intraductal carcinoma confined by benign myoepithelial cells was found in 60 cases and mostly exhibited high-grade cellular atypia, increased cellular proliferation and frequent genetic alterations (TP53, Her2-neu, androgen receptor). Intraductal carcinoma was absent only in the myoepithelial type of CEPA. In 26 cases, purely intraductal CEPA with extensive intraductal expansion was found. This suggests that there is a long period of intraductal growth before extraductal intracapsular infiltration of the PA. We identified two different histomorphological types of intraductal carcinoma, which we call 'clinging' and 'solid' types. In summary, combined histological, immunohistological and molecular data strongly support multistep carcinogenesis starting with intraductal carcinoma for all non-myoepithelial types of CEPA. The clinical significance of our finding of two histomorphological types of intraductal carcinoma (clinging and solid) is not yet clear. Intraductal carcinoma, intracapsular invasive CEPA and minor extracapsular invasive CEPA (up to about 6 mm) all show favourable prognosis and together comprise half of the cases in our study.

Metastatic HER-2-positive salivary gland carcinoma treated with trastuzumab and a taxane: a series of six patients

Metastatic salivary gland carcinoma is a rare malignancy. A subset of these tumors overexpresses the human epidermal growth factor receptor 2 (HER-2), which is considered a poor prognostic marker. Targeted therapy with the monoclonal antibody trastuzumab can be a treatment option in these patients. We describe six cases of metastatic salivary gland carcinoma treated with trastuzumab in combination with a taxane. Three of these patients had salivary duct cancer, two had mucoepidermoid carcinoma and one patient was treated for acinic cell carcinoma. The therapy was well tolerated. We observed five partial responses and a median progression free survival of 10.8 months, which compares favorably with the reported outcome of combination chemotherapy. One patient achieved a complete and durable remission. When HER-2 and androgen receptor were co-expressed, trastuzumab-based treatment appeared to be more active than androgen deprivation in our experience.

Molecular Pathology and Biomarkers

The field of salivary gland tumor biology is quite broad, given the numerous subtypes of both benign and malignant tumors originating from the major and minor salivary glands. Knowledge about the molecular pathology of these lesions is still limited, and there are few clinically useful diagnostic and prognostic biomarkers. However, recent discoveries of certain key genomic alterations, such as chromosome translocations, copy number alterations, and mutations, provide new insights into the molecular pathogenesis of these lesions and may help to better define them. It is also hoped that this new knowledge can help to guide therapy, but this translation has been somewhat slow to develop, perhaps due to the rarity of these tumors and the lack of large, randomized studies. However, because of the limitations inherent in what surgery and radiation can provide, there is an urgent need for understanding of the mechanisms of carcinogenesis in these tumors individually, so that chemotherapy and/or targeted therapy can be rationally selected.

Salivary duct carcinoma in the mandibular anterior region: The role of immunohistochemical markers in its definitive diagnosis

Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma arising from the ductal epithelium of salivary glands which rarely involves the minor salivary glands. The varied histological presentation in the minor salivary gland tumors makes them the most heterogeneous group of neoplasms, making the diagnosis a challenge. This report highlights the importance of immunohistochemical markers in the definitive diagnosis of SDC.

Salivary duct carcinoma: Clinicopathologic features, morphologic spectrum, and somatic mutations

BACKGROUND

Accurate diagnosis of salivary duct carcinoma requires a high index of suspicion and clinicopathologic correlation. Hallmark genetic changes that may provide novel therapeutic options are being explored.

METHODS

One hundred ninety salivary gland malignancies at Royal Prince Alfred Hospital (from 1989-2014) were reviewed. Human epidermal growth factor receptor 2 (HER2) and androgen receptor status were determined along with multigene profiling.

RESULTS

Twenty-three salivary duct carcinomas were identified, predominantly in men in their fifth to ninth decades of life. Facial nerve palsy (12%) and cervical lymph node metastases (82%) were present, and 96% received postoperative adjuvant therapy. Histologically, the tumors resembled high-grade invasive and in situ ductal carcinoma of the breast. Micropapillary, papillary, sarcomatoid, oncocytic, and mucinous variants were seen. The tumors showed androgen receptor (70%), HER2 amplification (30%), and HRAS, AKT1, PIK3CA, and NRAS mutations (22%; cumulative). The 5-year disease-free survival was 36%.

CONCLUSION

Salivary duct carcinoma demonstrates a wide histopathologic spectrum. Treatment strategies need to take androgen receptor, HER2 amplification, and PIK3CA mutation into account. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1838-E1847, 2016.

Prognostic factors and outcome analysis of salivary duct carcinoma

OBJECTIVE

Salivary duct carcinoma (SDC) is highly aggressive, with high rates of recurrence and nodal and distant metastases. The aim of the current study was to evaluate the clinical implication of EGFR and HER2 expression for predicting prognosis and to identify the factors associated with outcome.

METHODS

The medical records of 28 patients with SDC underwent surgery and adjuvant RT. Expression of c-erbB-2 and EGFR was determined immunohistochemically on the 25 SDC specimens. Disease-free survival (DFS), overall survival (OS) and distant metastasis-free survival (DMFS) were analyzed.

RESULTS

Three-year DFS, OS and DMFS rates were 38.3%, 78.1% and 45.7%, respectively. Expression of c-erbB-2 and EGFR was seen in 64% and 40%. c-erbB-2 and EGFR expression did not correlate with recurrence or metastasis. Advanced N classification and perineural invasion (PNI) were significant predictors of DFS and DMFS.

CONCLUSION

c-erbB-2 and EGFR expression did not correlate with recurrence or metastasis. Despite aggressive surgery and RT, approximately 50% of SDCs failed systemically. More effective therapy to inhibit distant metastases in patients with advanced N classification and PNI should be considered.

Androgen-Receptor Positive Lacrimal Sac Adenocarcinoma Demonstrating Long-Lasting Response to LHRH Analog Plus Abiraterone Treatment

Tumors arising at the lacrimal sac are extremely rare, as a limited number of cases have been reported worldwide. They are commonly primary and the majority of them are malignant and epithelial in origin. Adenocarcinomas account for a small percentage of these tumors. Treatment of local disease mainly includes complete surgical resection. However, metastatic disease has a poor prognosis and the development of new treatment strategies is highly important. Research efforts mainly focus on the identification of molecular targets for therapy. Herein, we describe for the first time a case of a patient with an androgen receptor expressing adenocarcinoma of the lacrimal sac that had an impressive response to abiraterone.

Human Epidermal Growth Factor Receptor 2 (HER2/neu) in Salivary Gland Carcinomas: A Review of Literature

The aim of our study is to assess the relation of human epidermal growth factor receptor 2 or HER2/neu with the development of salivary gland carcinomas and use of Herceptin in the treatment of these cancers. A literature search was conducted using MEDLINE accessed via the National Library of Medicine PubMed interface searching for articles from 1994 up to 2014 relating to the existence of HER-2 protein and gene in salivary gland carcinomas and HER2/neu targeted therapy, written in English language. Almost all the studies in literature reported a frequent over expression and amplification of HER2/nue in salivary duct carcinomas (SDC) compared to other salivary gland cancers. Herceptin given as a monotherapy was not effective. The data on Herceptin combined chemotherapy are potentially promising but inadequate to evaluate drug activity, as patients also received a variety of cytotoxic agents. Therefore, Herceptin contribution to tumour response outcomes could not be precisely determined and the total number of cases is not sufficient. It is recommended that further work involves a large series of HER2/neu positive salivary gland cancers (randomized control trial) treated with chemotherapy with and without Herceptin. This might need multi-institutional cooperation.

Sarcomatoid salivary duct carcinoma of the palate: a rare case report

Salivary duct carcinoma (SDC) is an uncommon neoplasm that most commonly occurs in major salivary glands, mainly the parotid gland. SDC is rarely found in the minor salivary glands of the oral cavity. This report presents an extremely rare case of sarcomatoid SDC originating in a minor salivary gland of the palate. The tumor was histologically characterized by the presence of both carcinomatous and sarcomatoid components. The patient presented with a painless mass in the right palate, which slowly increased in size over 20 years. The clinical course of the present case suggests that the tumor most probably developed as a result of malignant transformation of a preexisting benign tumor of the palatal salivary gland. This report describes the clinical and histologic features of this extremely rare case of sarcomatoid SDC with reference to the relevant literature.

HER2 aberrations in cancer: implications for therapy

Although anti-HER2 (human epidermal growth factor receptor 2) therapy is currently approved for breast, gastric, and gastroesophageal cancers overexpressing the HER2 protein or amplified for the HER2 gene, HER2 aberrations (gene amplification, gene mutations, and protein overexpression) are reported in other diverse malignancies. Indeed, about 1-37% of tumors of the following types harbor HER2 aberrations: bladder, cervix, colon, endometrium, germ cell, glioblastoma, head and neck, liver, lung, ovarian, pancreas, and salivary duct. Four HER2-targeted therapies have been approved for HER2-positive breast cancer: two antibodies (trastuzumab and pertuzumab), an antibody-drug conjugate (ado-trastuzumab emtansine), and a small molecule kinase inhibitor (lapatinib). In addition, afatinib, a small molecule kinase inhibitor that causes irreversible inhibition of EGFR (epidermal growth factor receptor) and HER2, was recently approved for EGFR-mutated non-small cell lung cancer. A large number of novel HER2-targeted agents are also in clinical trials. Herein we discuss the state of the art in understanding and targeting HER2 across anatomic tumor types.

Salivary duct carcinoma of the parotid gland: is adjuvant HER-2-targeted therapy required?

PURPOSE

Salivary duct carcinoma (SDC) of the parotid gland is a highly aggressive and uncommon tumor. Overexpression of human epidermal growth factor receptor 2 (HER-2) is characteristic of SDC. HER-2 overexpression is considered a poor prognostic marker for SDC, and anti-HER-2 therapy has been suggested as a therapeutic option.

MATERIALS AND METHODS

Two patients with SDC were analyzed for HER-2 overexpression and gene amplification using immunohistochemistry and fluorescence in situ hybridization.

RESULTS

In 1 patient, no expression of HER-2 was found. In the other patient, HER-2 was demonstrated. The patient with HER-2 overexpression had a worse prognosis, and trastuzumab proved to be an effective treatment.

CONCLUSIONS

The present results have also suggested that HER-2 overexpression is associated with a poor prognosis. Therefore, HER-2 status should be evaluated at least in the presence of advanced SDC, and targeted therapy should be considered in the adjuvant setting.

Complete Response to Trastuzumab-Based Chemotherapy in a Patient with Human Epidermal Growth Factor Receptor-2-Positive Metastatic Salivary Duct Carcinoma ex Pleomorphic Adenoma

Introduction

Carcinoma ex pleomorphic adenoma (CXPA) of the salivary glands has often a salivary duct carcinoma (SDC) component, which resembles ductal carcinoma of the breast and frequently overexpresses human epidermal growth factor receptor-2 (HER2). We report a case of metastatic CXPA with SDC component who was treated with trastuzumab-based chemotherapy and has had a durable complete response.

Case Report

A 74-year-old man was diagnosed with CXPA of the right parotid gland. The resected tumor was histologically diagnosed as CXPA with a predominant SDC component that showed strong positivity for HER2 protein and HER2 gene amplification. Multiple pulmonary metastatic lesions were detected after surgery, and combination chemotherapy with paclitaxel and trastuzumab was initiated. A complete response was confirmed after 7 treatment cycles, and no evidence of disease progression has been observed after 13 months of initiation of therapy.

Conclusions

This report suggests a potential utility of trastuzumab-based chemotherapy for HER2-positive CXPA.

Predictors of cervical lymph node metastasis in salivary gland cancer

BACKGROUND

This study compares clinicopathological parameters with novel molecular markers for predicting cervical lymph node metastasis in salivary gland cancer.

METHODS

Three hundred sixteen salivary gland carcinomas were included in this study. Genomic epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), phosphatase and tensin homolog (PTEN), and hepatocyte growth factor receptor (MET) was determined by fluorescence in situ hybridization (FISH). Chi-square tests, multivariate regression, and Kaplan-Meier survival analysis were used for statistics.

RESULTS

Nodal staging determines long-term survival. Clinicopathological parameters associated with positive neck nodes are advanced age (p = .006), T3/T4 classification, histological high-grade malignancy, and diagnosis of salivary duct carcinoma (p < .001 each). Neck node metastases also correlate with copy number gain of EGFR (p = .004) and HER2, aberration of MET, and deletion of PTEN (p < .001 each). Multivariate analysis showed SDC (p = .002) to be the strongest predictor of lymph node metastasis, followed by MET aberration (p = .009), T3/T4 classification (p = .017), PTEN deletion (p = .042), and adenocarcinoma not otherwise specified (NOS; p = .047).

CONCLUSION

The histological subtype is crucial for decisions regarding neck dissection. New molecular parameters may also indicate elective treatment of the neck.

A mucin-rich variant of salivary duct carcinoma with a prominent mucinous component, a tumor that mimics mucinous adenocarcinoma

The mucin-rich variant of salivary duct carcinoma (mSDC) is a rare type of salivary duct carcinoma. mSDC usually has both conventional SDC and mucinous adenocarcinoma-like areas. This article describes a first case of mSDC in which 95% of the tumor consisted of a mucinous area without no solid conventional SDC, so that the tumor mimicked mucinous adenocarcinoma. A 55-year-old man was evaluated for a 14 mm mass in the left submandibular gland. The tumor showed that floating tumor nests in a prominent mucinous lake. Some floating tumor nests had focal cribriform pattern with comedo necrosis, and all tumor cells had immunoreactivity for androgen receptor, gross cystic disease fluid protein 15, and Her-2/neu. A diagnosis of mSDC was rendered. mSDC with prominent mucinous component sometimes resembles mucinous adenocarcinoma. Identifying specific histological and immunohistochemical features of floating tumor nests in the mucinous area are important for the diagnosis.

Detection of novel actionable genetic changes in salivary duct carcinoma helps direct patient treatment

PURPOSE

Salivary duct carcinomas (SDC) are a rare and aggressive subtype of salivary gland cancers for which cytotoxic chemotherapy has limited efficacy. We investigated whether genotyping analysis could detect novel tumor-specific mutations that would help direct SDC patient treatment using targeted agents.

EXPERIMENTAL DESIGN

We genotyped 27 SDC archival specimens from patients followed at Massachusetts General Hospital and Massachusetts Eye and Ear Infirmary (Boston, MA) between 2000 and 2011. These included the tumors of 8 patients who were tested prospectively. Targeted mutational analysis of 13 clinically relevant cancer genes was conducted using SNaPshot multiplexed genotyping. FISH was conducted to detect HER2 gene amplification. Patient medical records and tumor histopathologic features were retrospectively reviewed.

RESULTS

Mutually exclusive genetic aberrations were detected in 15 of 27 (56%) tumors, including 2 (7%) mutations in BRAF, 5 (19%) mutations in PIK3CA, and 8 (30%) cases of HER2 gene amplification. To our knowledge, this is the first time that BRAF and PIK3CA mutations have been reported in this tumor type. Prospective clinical testing of 8 patients with SDC identified actionable genetic alterations in 6 tumors and influenced therapeutic decisions for all 6 patients.

CONCLUSION

SNaPshot molecular profiling identified novel genetic changes in SDCs, expanded the therapeutic options for patients with this rare tumor, and is changing SDC management at our institution. These findings highlight the importance of using broad-based genetic profiling to expedite the identification of effective-targeted therapies for patients with rare malignancies.

Management and outcome of salivary duct carcinoma in major salivary glands

Salivary duct carcinoma (SDC) is a rare and aggressive malignancy with poor prognosis. Its histomorphology is distinctly reminiscent of the ductal carcinoma of the breast. We reviewed the treatment and outcome of SDCs at a single tertiary care centre. Twenty-five cases of SDC of major salivary gland origin, diagnosed and treated at the Department of Otolaryngology, Head and Neck Surgery, Helsinki University Central Hospital, Helsinki, Finland, during a 14-year period from 1997 to 2011, were reviewed retrospectively. Survival outcome was analyzed for 18 patients with a minimum follow-up of 24 months. There were 16 male (64 %) and 9 female (36 %) patients with a median age of 61 years (range 36-82 years). The majority of the cases occurred in the parotid gland (n = 21, 84 %) followed by the submandibular gland (n = 4, 16 %). The primary treatment consisted of surgical resection in all cases and 17 (68 %) patients also underwent neck dissection. Most of the patients (n = 18, 72 %) were treated with postoperative radiotherapy. Seven patients (28 %) had a disease recurrence within a median follow-up time of 15 months (range 3-27 months). In the group (n = 18) with a minimum follow-up time of 24 months, the 2- and 5-year overall and disease-specific survival rates were 66, 41 % and 75, 55 %, respectively. These results confirm the aggressive nature of SDCs in major salivary glands. Diagnostics and management of these tumours need to be centralized in experienced surgical Head and Neck Oncology Centres, and new treatment strategies should be investigated.

Novel therapeutic strategies for malignant salivary gland tumors: lessons learned from breast cancer

Malignant salivary gland tumors (MSGTs) account for 2–6% of all head and neck cancers. Despite the rarity, MSGTs have been of great interest due to a wide variety of pathological features and high metastasis rates resulting in poor prognosis. Surgical resection followed by radiation therapy represents the main treatment of this malignancy. Adjuvant therapy is reserved for the management of local recurrence, no longer amenable to additional local therapy, and for metastasis. Based on the studies from other types of tumors, particularly breast cancer, the expression and function of sex steroid hormone receptors in cancer have been extensively studied and applied to diagnosis and treatment. Although a number of studies in MSGTs have been published, the rationale for hormone therapy is still controversial due to the disparate results and insufficient number of cases. However, some recent reports have demonstrated that certain salivary gland neoplasms are similar to breast cancer, not only in terms of the pathological features, but also at the molecular level. Here, we shed light on the biological similarity between MSGTs and certain types of breast cancer, and describe the potential use of hormone and additional therapies for MSGTs.

TRK-A, HER-2/neu, and KIT Expression/Activation Profiles in Salivary Gland Carcinoma

Salivary duct carcinomas (SDCs) and adenoid cystic carcinomas (ACCs) are the most aggressive and the most frequent carcinomas of the salivary glands, respectively. Little is known about them in terms of molecular/biochemical characterization and conventional treatments are ineffective. On cryopreserved material, we analyzed the expression/activation status of TRK-A, HER-2/neu, and KIT receptors by means of immunoprecipitation and Western blot analysis experiments, and the presence of their cognate ligands by means of Western blot analysis and/or reverse transcription-polymerase chain reaction in 9 SDCs, 12 ACCs, and 8 normal glands. The amplification status of HER-2/neu was also investigated by means of fluorescent in situ hybridization analysis on fixed material. The receptor tyrosine kinase (RTK)-deregulated profile of the SDCs was characterized by the overexpression of activated TRK-A in the presence of its ligand, and the overexpression of HER-2/neu sustained by gene amplification. The RTK signature of the ACCs was represented by the overexpression of activated KIT and TRK-A and their cognate ligands, and the overexpression of activated HER-2/neu, in the absence of gene amplification, possibly sustained by epidermal growth factor receptor heterodimerization. In conclusion, SDCs and ACCs, although sharing TRK-A autocrine loop activation, have different pathologically activated RTK-deregulated profiles that may be potential targets for pharmacological RTK inhibitors.

Targeted therapy with trastuzumab for advanced salivary ductal carcinoma: case report and literature review

Salivary duct carcinoma (SDC) is a rare subtype of salivary gland carcinoma and is considered to be a high-grade aggressive tumor with morphological resemblance to ductal carcinoma of the breast. We present a case of a patient who suffered from metastatic SDC that was positive for human epidermal growth factor receptor-2 (HER-2) and attained complete objective response, as seen on PET-CT after combined treatment with paclitaxel, carboplatin, and trastuzumab.

Low-grade salivary duct carcinoma of the parotid gland: report of a case with immunohistochemical analysis

Salivary duct carcinoma (SDC) is a highly aggressive malignancy of the salivary glands. However, one type of SDC, which shows minimal invasion and better prognosis, is known as low-grade SDC (LG-SDC). This report presents an additional case of LG-SDC of the parotid gland. The patient was a 38-year-old Japanese woman who noticed painless swelling of the left parotid region. Grossly, the cut surface of the tumor was cystic. Microscopically, the tumor showed a multicystic pattern, which was lined by eosinophilic to clear atypical cells with cribriform or Roman bridge patterns. An immunohistochemical examination revealed the tumor was positive for cytokeratin (CK) 7 and epithelial membrane antigen, partially positive for androgen receptor and gross cystic disease fluid protein-15, and diffusely positive for Her-2/Neu, progesterone, and estrogen receptors. The cancer cells showed focal immunopositivity for S-100 protein. Immunostaining for p63, CK14, and calponin showed an in situ pattern in most areas of this tumor, whereas the tumor showed minimal invasion. The cancer cells were diffusely positive for MUC1 and MUC6 and focally positive for MUC2 and MUC4. Finally, the tumor was diagnosed to be LG-SDC. The differential diagnosis and the mucin pattern were evaluated.

Overexpression of sphingosine kinase 1 is associated with salivary gland carcinoma progression and might be a novel predictive marker for adjuvant therapy

BACKGROUND

Overexpression of sphingosine kinase-1 (SPHK1) has been demonstrated to be associated with the development and progression in various types of human cancers. The current study was to characterize the expression of SPHK1 in salivary gland carcinomas (SGC) and to investigate the association between SPHK1 expression and progression of SGC.

METHODS

The expression of SPHK1 was examined in 2 normal salivary gland tissues, 8 SGC tissues of various clinical stages, and 5 pairs of primary SGC and adjacent salivary gland tissues from the same patient, using real-time PCR and western blot analysis. Furthermore, the SPHK1 protein expression was analyzed in 159 clinicopathologically characterized SGC cases by immunohistochemistry. Statistical analyses were performed to determine the prognostic and diagnostic associations.

RESULTS

SPHK1 expression was found to be markedly upregulated in SGC tissues than that in the normal salivary gland tissues and paired adjacent salivary gland tissues, at both mRNA and protein levels. Statistical analysis revealed a significant correlation of SPHK1 expression with the clinical stage (P = 0.005), T classification (P = 0.017), N classification (P = 0.009), M classification (P = 0.002), and pathological differentiation (P = 0.013). Patients with higher SPHK1 expression had shorter overall survival time, whereas patients with lower SPHK1 expression had better survival. Importantly, patients in the group without adjuvant therapy who exhibited high SPHK1 expression had significantly lower overall survival rates compared with those with low SPHK1 expression. Moreover, multivariate analysis suggested that SPHK1 expression might be an independent prognostic indicator for the survival of SGC patients.

CONCLUSIONS

Our results suggest that SPHK1 expression is associated with SGC progression, and might represent as a novel and valuable predictor for adjuvant therapy to SGC patients.

Parotid carcinoma: Current diagnostic workup and treatment

In this review we present recent progress in diagnostic workup, prognostic evaluation, treatment options and resulting outcomes. Whenever possible, complete resection remains the mainstay of treatment. Sacrifice of facial nerve branches is reserved for the clinically or electromyographically dysfunctioning facial nerve. Clinical or radiological neck disease demands combined surgery and radiotherapy. Treatment of the N0 neck is indicated for advanced stage-high grade tumors but the question remains unanswered whether this should be surgical or radiotherapeutic elective treatment. Surgery alone will cure low stage, low grade tumors, that show no additional negative prognostic factors following adequate resection. In all other tumors postoperative radiotherapy will improve locoregional control. This approach results in good locoregional control, in a way that distant metastasis remains the typical presentation of treatment failure. In this setting, the results of systemic treatment today remain limited, but a huge effort in the molecular biology field has been done to introduce targeted therapy into this domain of head and neck cancer. Disease control remains variable within the patient population. This variation can increasingly be predicted by systems that incorporate the combined information of multivariately identified and quantified prognostic factors into an individualized prognosis for the parotid carcinoma patient.

Current concepts in research related to oncogenes implicated in salivary gland tumourigenesis: a review of the literature

BACKGROUND

Salivary gland tumours are relatively uncommon and there exists considerable difficulty in decisions regarding prognosis and management, as well as diagnostic uncertainty that has implications for treatment.

METHOD

Literature pertaining to individual oncogenes has been reviewed and commented upon, specifically looking at the role of these as diagnostic and prognostic markers and as potential targets for treatments.

RESULTS

kit, PLAG1, Mect1-Maml2, HMGIC, HER2/neu, ras, c-fos and Sox-4 all have seminal small-scale studies in the literature with potential for further research and eventual clinical applications.

CONCLUSION

A wide variety of oncogenes are implicated in salivary gland tumourigenesis, with evidence being confined to small murine or in vitro studies more often than not. There are possible roles for different oncogenes in therapeutics, prognosis and management of specific salivary gland tumours.

Immunohistochemical evaluation of androgen receptor, HER-2/neu, and p53 in benign pleomorphic adenomas

CONTEXT

Immunohistochemical stains for androgen receptor (AR), HER-2/neu, and p53 are used as diagnostic markers associated with malignancy in several histologic types of salivary gland tumors. These markers may be useful in differentiating pleomorphic adenoma with cytologic atypia from intracapsular carcinoma ex pleomorphic adenoma (CXPA), as these tumors are often difficult to distinguish on the basis of morphology alone.

OBJECTIVE

To determine whether AR, HER-2/neu, and p53 expression can be seen in entirely benign pleomorphic adenomas.

DESIGN

Androgen receptor, HER-2/neu, and p53 immunoreactivity was assessed in 41 histologically and clinically benign pleomorphic adenomas.

RESULTS

A total of 3 of 41 pleomorphic adenomas exhibited multifocal areas with moderate staining for HER-2/ neu and AR. The positive staining was mainly confined to the epithelial component, where the ductal epithelium showed no cytologic atypia. Immunoreactivity for p53 was observed in the epithelial component of 5 of 41 cases, none of which stained for HER-2/neu and AR. Mean mitotic rate and Ki-67 index were 1 per 10 high-powered fields and 2.7% in HER-2/neu- and AR-positive cases and 1 per 10 high-powered fields and 2.2% in p53-positive cases.

CONCLUSIONS

HER-2/neu, AR, and p53 are expressed in a subset of histologically and clinically benign pleomorphic adenomas. These markers cannot be used to reliably predict early carcinomatous transformation in pleomorphic adenoma.

Salivary gland malignancies: the role for chemotherapy and molecular targeted agents

Salivary gland tumors are a rare and clinically diverse group of neoplasms that represent less than 1% of all malignancies. In locoregional recurrent or metastatic disease, systemic therapy is the standard approach. Numerous phase II studies with small sample sizes have assessed the activity of different cytotoxic agents, either alone or in combination. For these agents, the objective response rates are generally modest, ranging from 15% to 50%. Duration of response is typically cited in the range of 6 to 9 months. Further evaluation of novel therapies is mandated in this disease. With the emergence of molecular targeted therapy, these tumors become optimal candidates for trials of investigational drugs and established drugs for new indications. Often, salivary gland carcinomas are indolent. As such, one should wish only to treat patients with progressive disease. Study designs must incorporate stringent inclusion criteria to enable accurate reporting of disease response and stabilization, especially in the evaluation of new drugs and novel combinations. Salivary gland-focused cooperative groups are necessary in order to accrue patients to these clinical trials and establish new treatment guidelines for these patients.

Biological therapy of salivary duct carcinoma

BACKGROUND

The incidence of human epidermal growth factor receptor 2 positivity in salivary duct carcinoma ranges from 25 to 100 per cent and is associated with a poor outcome. Salivary duct carcinoma has significant pathological similarities to ductal carcinoma of the breast.

METHODS AND RESULTS

A 49-year-old man developed lung and liver metastasis a few months after surgery and adjuvant radiotherapy for salivary duct carcinoma of the parotid gland. There was no response to palliative chemotherapy with doxorubicin. We followed the biological model of breast cancer, whereby two-thirds of human epidermal growth factor receptor 2 positive patients respond to a combination of docetaxel and human epidermal growth factor receptor 2 blocker (trastuzumab). A durable, complete response was achieved with this combination. A rationalised treatment approach targeting the biological characteristics of salivary duct carcinoma had proven successful.

A comparative study between mixed-type tumours from human salivary and canine mammary glands

BACKGROUND

In comparative pathology, canine mammary tumours have special interest because of their similarities with human breast cancer. Mixed tumours are uncommon lesions in the human breast, but they are found most frequently in the mammary gland of the female dogs and in the human salivary glands. The aim of the study was to compare clinical, morphological and immunohistochemical features of human salivary and canine mammary gland mixed tumours, in order to evaluate the latter as an experimental model for salivary gland tumours.

METHODS

Ten examples of each mixed tumour type (human pleomorphic adenoma and carcinomas ex-pleomorphic adenomas and canine mixed tumour and metaplastic carcinoma) were evaluated. First, clinical and morphologic aspects of benign and malignant variants were compared between the species. Then, streptavidin-biotin-peroxidase immunohistochemistry was performed to detect the expression of cytokeratins, vimentin, p63 protein, estrogen receptor, beta-catenin, and E-cadherin.

RESULTS

After standardization, similar age and site distributions were observed in human and canine tumours. Histological similarities were identified in the comparison of the benign lesions as well. Metaplastic carcinomas also resembled general aspects of carcinomas ex-pleomorphic adenomas in morphological evaluation. Additionally, immunohistochemical staining further presented similar antigenic expression between lesions.

CONCLUSION

There are many similar features between human salivary and canine mammary gland mixed tumours. This observation is of great relevance for those interested in the study and management of salivary gland tumours, since canine lesions may constitute useful comparative models for their investigations.

Phase II Study of Lapatinib in Recurrent or Metastatic Epidermal Growth Factor Receptor and/or erbB2 Expressing Adenoid Cystic Carcinoma and Non–Adenoid Cystic Carcinoma Malignant Tumors of the Salivary Glands

Purpose

Expression of erbB2 and/or epidermal growth factor receptor (EGFR) is associated with biologic aggressiveness and poor prognosis in malignant salivary gland tumors (MSGTs). This phase II study was conducted to determine the antitumor activity of lapatinib, a dual inhibitor of EGFR and erbB2 tyrosine kinase activity, in MSGTs.

Patients and Methods

Patients with progressive, recurrent, or metastatic adenoid cystic carcinoma (ACC) immunohistochemically expressing at least 1+ EGFR and/or 2+ erbB2 were treated with lapatinib 1,500 mg daily, in a two-stage cohort. Patients with non-ACC MSGTs were treated as a separate single-stage cohort.

Results

Of 62 patients screened, 29 of 33 (88%) ACC and 28 of 29 (97%) non-ACC patients expressed EGFR and/or erbB2. Forty patients with progressive disease were enrolled onto the study. Among 19 assessable ACC patients, there were no objective responses, 15 patients (79%) had stable disease (SD), nine patients (47%) had SD ≥ 6 months, and four patients (21%) had progressive disease (PD). For 17 assessable non-ACC patients, there were no objective responses, eight patients (47%) had SD, four patients (24%) had SD ≥ 6 months, and nine patients (53%) had PD. The most frequent adverse events were grade 1 to 2 diarrhea, fatigue, and rash. Eight paired tumor biopsies for correlative studies were procured; results did not correlate with clinical outcome.

Conclusion

Although no responses were observed, lapatinib was well tolerated, with prolonged tumor stabilization of ≥ 6 months in 36% (95% CI, 21% to 54%) of assessable patients. The antitumor effects of lapatinib in MGSTs appear mainly cytostatic, hence evaluation of other molecular targeted agents, or combinations with lapatinib, may be considered. Continued efforts should be made to gain better understanding into the biology of this heterogeneous group of malignancies.

Malignancies of the head and neck: the role for molecular targeted agents

Although cancers arising in the head and neck region are a diverse group of malignancies, a unifying thread remains a poor overall survival for patients with advanced, recurrent or metastatic disease. Treatment strategies need to evolve and improve upon established therapeutic practices. As the process of cancer evolution is understood to be derived from aberrations in genetic and epigenetic processes, molecularly targeted agents offer attractive therapeutic options by restoring normal control of oncogenic processes. The direct role for the treatment of squamous cell carcinoma of the head and neck, nasopharynx and salivary gland carcinomas with these novel, molecularly targeted agents are reviewed and their potential to improve on the existing standard of care is further explored.

Systemic therapy in the palliative management of advanced salivary gland cancers

Cancers of the salivary glands are unusual lesions that vary widely in their histologic appearance and molecular characteristics. Likewise, there is a wide spectrum of biologic behavior, ranging from low-grade, minimally invasive tumors, to highly lethal malignancies. There are few data on the role of systemic therapies in the management of these cancers, and chemotherapy is generally reserved for the palliative management of advanced disease that is not amenable to local therapies such as surgery and/or radiation. The majority of patients for whom systemic therapy is considered will have either adenoid cystic carcinoma, mucoepidermoid carcinoma, or high-grade adenocarcinoma. This article will review the available literature regarding the use of palliative chemotherapy for patients with advanced salivary gland cancer of these histologies, with an emphasis on the potential role of targeted agents. There is a need for a determined, coordinated effort to conduct high-quality clinical trials in patients with these rare cancers.

Timely DNA vaccine combined with systemic IL-12 prevents parotid carcinomas before a dominant-negative p53 makes their growth independent of HER-2/neu expression

Double transgenic mice overexpressing the transforming rat HER-2/neu oncogene and the mutated p53, with both dominant-negative and a gain-of-function properties, display early aggressive and metastasizing parotid tumors. Multiple acinar and ductal hyperplasia foci overexpressing the HER-2/neu gene product are evident at wk 5 and progress to poorly differentiated carcinoma by wk 7. Mice die before wk 18 with invasive carcinomas and multiple metastases that no longer express HER-2/neu. A combination of repeated electroporations of plasmids coding for the extracellular and transmembrane domains of the rat HER-2/neu receptor with systemic IL-12 administrations started when the parotids that present diffuse hyperplasia protected all female and 50% of the male mice until the close of the experiment at wk 40. This combined treatment began when multifocal in situ carcinomas that were already present cured 33% of the females and 25% of the males. The most prominent immunologic features associated with the antitumor protection were the production of high titers of anti-HER-2/neu Abs and the nonappearance of cell-mediated cytotoxic reactivity. In conclusion, anti-HER-2/neu vaccination combined with systemic IL-12 control parotid carcinomas as far as p53 mutation makes their growth independent of HER-2/neu expression.

Anti-erbB-2 antibody trastuzumab in the treatment of HER2-amplified breast cancer

Human epidermal growth factor receptor-2 (HER2/erbB-2) is a member of a family of four transmembrane receptor tyrosine kinases that regulate cell growth, survival and differentiation via multiple signal transduction pathways. Amplification of the HER2 gene occurs in 20-25% of human breast cancers. This amplification event is an independent adverse prognostic factor as well as a predictive factor for increased response to doxorubicin-based combination chemotherapy, response to trastuzumab and decreased response to hormonal therapy. Methods for detecting protein overexpression or gene amplification in clinical tumor specimens include immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) techniques, with the latter considered by some to be more accurate. Trastuzumab (Herceptin) is a recombinant humanized monoclonal antibody which targets an epitope in the extracellular domain of the HER2 protein. Preclinical models demonstrated that this antibody has significant anti-tumor activity as a single agent and has synergy with certain chemotherapeutic drugs. Phase II and III clinical trials performed in women with metastatic breast cancer that overexpress HER2 have shown that trastuzumab has clinical activity when used as first-, second- or third-line monotherapy, and improves survival when used as first-line therapy in combination with chemotherapy. Newer combinations with numerous chemotherapeutic drugs have also shown significant clinical activity in phase II studies. In all of these trials, trastuzumab was generally well-tolerated, but cardiac toxicity (particularly when the antibody was combined with anthracyclines) was an unexpected adverse effect. Although trastuzumab is currently usually administered on a weekly intravenous schedule, evidence suggests that a triple dose of the drug given once every three weeks has a pharmacokinetic profile expected to be equally efficacious. Neither the optimal schedule nor the optimal duration of trastuzumab therapy has yet been clearly defined in controlled clinical trials. Current clinical investigations of trastuzumab include its use in both the adjuvant and neoadjuvant settings as well as in combination with other chemotherapy drugs or new biologic targeted agents.