Expression of HER-2/neu gene and protein in salivary duct carcinomas of parotid gland as revealed by fluorescence in-situ hybridization and immunohistochemistry

HER2-targeted therapies for salivary gland cancers

Salivary gland cancers (SGCs) are a heterogeneous group of rare tumors including various histological subtypes with different molecular profiling. Human epidermal growth factor receptor 2 (HER2) is one of the most intriguing and studied molecular alterations with prognostic and predictive roles. Indeed, HER2 overexpression is commonly correlated with aggressive histological subtypes and poorer prognosis. However, HER2 may represent the target of personalized treatment. We performed a literature review of use of anti-HER2 targeted agents for treatment of recurrent or metastatic SGCs. The efficacy and safety of anti-HER2 were firstly evaluated in patients affected with other solid tumors, mostly breast and gastric cancers. For SGCs the literature is mainly comprised of case reports or case series and small clinical trials. The most common used drug is trastuzumab in combination with chemotherapy (i.e. taxanes, capecitabine, carboplatin, eribulin) or with another anti-HER2 targeted agent (i.e. pertuzumab). The use of anti-HER2 therapies induces improvement in clinical responses, which are mostly durable. Besides, new anti-HER2 drugs such as antibody-drug conjugates (ADC) (i.e. trastuzumab emtansine, trastuzumab deruxtecan) have been introduced in this setting inducing further therapeutic advances. Anti-HER2 treatment strategy is emerging as potentially effective in selected HER2 overexpressing SGCs. However, prospective and multicentric clinical trials are needed to evaluate the efficacy of these therapeutic regimens within larger cohorts and to assess the most appropriate treatment sequence strategy.

ERBB2 Amplification and HER2 Expression in Salivary Duct Carcinoma: Evaluation of Scoring Guidelines and Potential for Expanded Anti-HER2 Therapy

Salivary duct carcinoma (SDC) is aggressive with limited therapeutic options. A subset of SDC display human epidermal growth factor receptor 2 (HER2) protein overexpression by immunohistochemistry, and some show ERBB2 gene amplification. Guidelines for HER2 scoring are not firmly established. Recent advances in breast carcinoma have established a role for anti-HER2 therapies in lesions with low HER2 expression lacking ERBB2 amplification. Delineating HER2 staining patterns in SDC is critical for evaluating anti-HER2 treatments. In total, 53 cases of SDC resected at our institution between 2004 and 2020 were identified. Androgen receptor (AR) and HER2 immunohistochemistry and ERBB2 fluorescence in situ hybridization were performed in all cases. AR expression was scored for percentage positive cells and categorized as positive (>10% of cells), low positive (1%-10%), or negative (<1%). HER2 staining levels and patterns were recorded, scored using 2018 ASCO/CAP guidelines, and categorized into HER2-positive (3+ or 2+ with ERBB2 amplification), HER2-low (1+ or 2+ without ERBB2 amplification), HER2-very low (faint staining in <10% of cells), or HER2-absent types. Clinical parameters and vital status were recorded. Median age was 70 years, with a male predominance. ERBB2-amplified tumors (11/53; 20.8%) presented at lower pT stages (pTis/pT1/pT2; P = .005, Fisher exact test) and more frequently had perineural invasion (P = .007, Fisher exact test) compared with ERBB2 nonamplified tumors; no other pathologic features differed significantly by gene amplification status. In addition, 2+ HER2 staining by 2018 ASCO/CAP criteria was most common (26/53; 49%); only 4 cases (8%) were HER2-absent status; 3+ HER2 staining was found in 9 tumors, and all were ERBB2 amplified. Six patients with HER2-expressing tumors received trastuzumab therapy, including 2 with ERBB2-amplified tumors. Overall survival and recurrence-free survival did not differ significantly based on ERBB2 status. This work suggests that 2018 ASCO/CAP guidelines for HER2 evaluation in breast carcinoma could be applied to SDC. Our findings also show broad overexpression of HER2 in SDC raising the possibility that more patients may benefit from anti-HER2-directed therapies.

Role of HER2 in Prognosis of Salivary Duct Carcinoma: A Systematic Review and Meta-Analysis

OBJECTIVES

Salivary duct carcinoma (SDC) is a rare, aggressive malignancy with a poor prognosis. These tumors frequently stain positive for HER2/ErbB2, but data on the prognostic significance of HER2 status in SDC are mixed. We sought to determine whether HER2 status affects survival outcomes in SDC.

METHODS

PubMed, Embase, and Web of Science databases were searched from inception to October 2020. Eligibility was restricted to studies reporting HER2/ErbB2 overexpression in histologically confirmed de novo SDC or SDC ex pleomorphic adenoma, with corresponding overall (OS) and disease-free (DFS) survival measures. Separate multivariable and univariable meta-analyses were performed using random-effects models. Statistical heterogeneity was estimated by Cochran's Q and I² tests. Funnel plots were generated and Egger's test was used to assess for publication bias. The risk of bias was assessed with the Newcastle-Ottawa Scale.

RESULTS

Of 183 unique citations, 14 studies of 663 patients were included. Most included studies determined HER2 status according to ASCO/CAP guidelines. The univariable meta-analysis did not reveal an effect between HER2 status and OS (HR 1.09, 95% CI 0.84-1.42). In the multivariable analysis, HER2 positivity was associated with a HR of 1.49 for OS (95% CI 0.96-2.30). Fewer studies reported data for DFS than OS, with no relationship between HER2 status and DFS found on multivariable or univariable meta-analyses.

CONCLUSION

In patients with salivary duct carcinoma, HER2 positivity was not found to be associated with worse overall survival. This information may be useful when counseling patients and considering treatment options. Laryngoscope, 133:476-484, 2023.

Case report: ado-trastuzumab as second-line treatment in HER2 positive salivary duct carcinoma

The objective of this report is to present the use and efficacy of ado-trastuzumab as an advanced line of therapy in salivary duct carcinoma (SDC) patient. An 84-year-old gentleman diagnosed with metastatic salivary duct tumor harboring overexpressed human epidermal growth factor receptor-2 has gone through resection surgery. The first line of treatment included initial doublet chemotherapy combined with trastuzumab, which was continued later as maintenance. PET-CT follow-up for 4 years has demonstrated no evidence of disease. However, upon recurrence, use of Ado-trastuzumab emtansine was prompted as second-line of treatment. This targeted patient-tailored therapy has accomplished a complete response. The effectiveness of ado-trastuzumab emtansine was notable within a short time period of two treatment cycles leading to full recovery. Specific agents aimed at altered oncogenes should be considered as a potential drug of choice in neoadjuvant HER2 positive SDC.

PAX-8 Expression in Salivary Duct Carcinoma

Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma resembling breast ductal carcinoma. It accounts for ~10% of malignant tumors of the salivary glands. Most cases show expression of CK7 and androgen receptor. PAX-8 is a transcription factor, with expression reported in renal, Müllerian, and thyroid carcinomas. Previous studies have described an absence of PAX-8 immunostaining in most primary salivary gland neoplasms, including SDCs. However, PAX-8 expression is frequently found in neoplasms that can metastasize to salivary glands, suggesting the possibility that this protein can be used to differentiate SDC from secondary neoplastic involvement of the salivary gland. We evaluated the expression of PAX-8 in 14 cases of SDC from our institution. One case showed diffuse moderate to strong PAX-8 positivity, while 2 tumors showed focal weak staining. Therefore, we conclude that although the majority of SDC are negative for PAX-8, rare diffuse positivity can be seen in these primary salivary gland tumors. This could potentially pose difficulty in ruling out metastatic disease from another PAX-8-positive primary neoplasm.

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.

Adjuvant Treatment of the Salivary Duct Carcinoma with Her2 Overexpression

Malignant salivary gland tumors form 11% of all head and neck tumors. Salivary duct carcinoma (SDC) of the parotid gland is an uncommon and highly aggressive tumor accounting for 2% of all salivary gland malignancies. The fourth edition of the WHO Classification of Head and Neck Tumors reported global annual incidence of 0.4–2.6/100,000 people. Standard treatment for SDC is wide surgical resection along with lymph node dissection followed by adjuvant radiation therapy. The role of adjuvant chemotherapy is not known. Here, we present a case of an SDC of the parotid gland in a 55-year-old female. She presented with a painless swelling behind her right ear. Surgery was performed, and total right parotidectomy was done along with selective neck dissection (levels II, III, VA). The pathology report concluded that it was a G3 (poorly differentiated) SDC (micropapillary variant) with lymphovascular and perineural invasion. The clinical stage of the disease was T4aN2bM0. Adjuvant therapy consisted of concurrent radiation (TD 66 Gy) and chemotherapy with weekly paclitaxel (45 mg/m²), carboplatin (AUC 1.5), and trastuzumab (2 mg/kg; THC) for 6 weeks followed by 4 cycles of THC every 3 weeks. Adjuvant trastuzumab was continued for a total of 1 year. She is still without the evidence of the disease 7 years later. The consensus regarding the use of adjuvant chemotherapy does not exist. Based on all the data that have been presented before, the conclusion is that we need new treatment modalities to improve the outome of this aggressive disease.

HER2-positive metastatic, parotid salivary duct carcinoma treated with a trastuzumab/pertuzumab-based chemotherapy: A case report

This case highlights the rare entity, salivary duct carcinoma (SDC), which is difficult to diagnose and manage. It is the first published case of a metastatic, HER2-positive parotid SDC successfully treated by a dual anti-HER2 treatment associated to a chemotherapy.

Increased ERBB2 Gene Copy Numbers Reveal a Subset of Salivary Duct Carcinomas with High Densities of Tumor Infiltrating Lymphocytes and PD-L1 Expression

Salivary duct carcinoma (SDC) commonly expresses androgen receptor (AR) and HER2, giving rise to treatment implications. SDC may also express programmed-death-ligand-1 (PD-L1), a predictive marker of response to checkpoint inhibitors. PD-L1 can be associated with genomic instability and high density of tumor infiltrating lymphocytes (TILs). Evaluation of HER2 immunohistochemistry (IHC) in SDC is not standardized, and relationships between ERBB2 copy numbers, PD-L1 expression and TILs in SDC are unknown. We evaluated 32 SDCs for HER2, AR and PD-L1 expression (IHC), ERBB2 status (FISH) and TILs (slide review). HER2 was scored with three different systems (breast, gastric, proposed salivary gland). PD-L1 was evaluated with the combined positive score. Most patients were older men, presenting at advanced clinical stage with nodal or distant metastases. During follow-up (mean 5 years, range 6 months to 21 years), 25 of the 32 patients (78%) died of SDC. We propose a HER2 IHC scoring system which accurately predicts underlying ERBB2 amplification or increased copy numbers in SDC. Most tumors had increased ERBB2 copy numbers (19/32 amplification, 6/32 aneusomy), a finding associated with higher TIL densities (p = 0.045) and PD-L1 expression (p = 0.025). Patients with TILs ≥ 40% had better prognoses (Log-Rank p = 0.013), with TILs being favorable prognosticators in univariate analysis (Hazard ratio: 0.18, p = 0.024). A subset of SDCs with increased ERBB2 copy numbers have higher TILs and PD-L1 expression. TILs ≥ 40% are associated with better prognosis.

Major and minor salivary gland tumours

Salivary glands carcinomas are very rare epithelial malignant tumors. In 2013 in Europe, 7800 new diagnoses were estimated, 8.5 % of all head and neck cancer. The last WHO classification (2017) counts more than 20 malignant histotypes, this variety as well as the rarity of some of them needs a skilled pathologist for diagnosis. Surgery remains the mainstay of management followed by radiation in high-grade and high-risk pathological features cases. The intensity modulated radiotherapy (IMRT) should be preferred over conformational radiotherapy techniques as adjuvant and exclusive treatment in advanced cases. Particle radiotherapy (i.e. protons, carbon ions) can have a role in advanced/unresectable disease since it was proved to have better results over photons in loco-regional control both in adenoid cystic carcinoma and in other histotypes. Although chemotherapy is still the most frequent treatment for metastatic patients, several new compounds (i.e. anti-angiogenic agents, tailored agents, checkpoint inhibitors) are under investigation.

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.

The Role of Molecular Testing in the Differential Diagnosis of Salivary Gland Carcinomas

Salivary gland neoplasms are a morphologically heterogenous group of lesions that are often diagnostically challenging. In recent years, considerable progress in salivary gland taxonomy has been reached by the discovery of tumor type-specific fusion oncogenes generated by chromosome translocations. This review describes the clinicopathologic features of a selected group of salivary gland carcinomas with a focus on their distinctive genomic characteristics. Mammary analog secretory carcinoma is a recently described entity characterized by a t(12;15)(p13;q25) translocation resulting in an ETV6-NTRK3 fusion. Hyalinizing clear cell carcinoma is a low-grade tumor with infrequent nodal and distant metastasis, recently shown to harbor an EWSR1-ATF1 gene fusion. The CRTC1-MAML2 fusion gene resulting from a t(11;19)(q21;p13) translocation, is now known to be a feature of both low-grade and high-grade mucoepidermoid carcinomas associated with improved survival. A t(6;9)(q22-23;p23-34) translocation resulting in a MYB-NFIB gene fusion has been identified in the majority of adenoid cystic carcinomas. Polymorphous (low-grade) adenocarcinoma and cribriform adenocarcinoma of (minor) salivary gland origin are related entities with partly differing clinicopathologic and genomic profiles; they are the subject of an ongoing taxonomic debate. Polymorphous (low-grade) adenocarcinomas are characterized by hot spot point E710D mutations in the PRKD1 gene, whereas cribriform adenocarcinoma of (minor) salivary glands origin are characterized by translocations involving the PRKD1-3 genes. Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma with morphologic and molecular features akin to invasive ductal carcinoma of the breast, including HER2 gene amplification, mutations of TP53, PIK3CA, and HRAS and loss or mutation of PTEN. Notably, a recurrent NCOA4-RET fusion has also been found in SDC. A subset of SDC with apocrine morphology is associated with overexpression of androgen receptors. As these genetic aberrations are recurrent they serve as powerful diagnostic tools in salivary gland tumor diagnosis, and therefore also in refinement of salivary gland cancer classification. Moreover, they are promising as prognostic biomarkers and targets of therapy.

Acantholytic Squamous Cell Carcinoma and Salivary Duct Carcinoma Ex-pleomorphic Adenoma of the Submandibular Gland: A Report of Two Extremely Rare Cases with an Immunohistochemical Analysis

Carcinoma ex pleomorphic adenoma (CXPA) is a malignant tumor of the salivary gland that arises from pleomorphic adenoma (PA). Squamous cell carcinoma (SCC) is extremely rare in the salivary glands. We report two cases of acantholytic SCC (ASCC) ex PA. Case 1 involved a 72-year-old female, and case 2 involved a 67-year-old male. Histologically, both cases involved PA, and salivary duct carcinoma (SDC) components, which were positive for androgen receptor (AR) and gross cystic disease fluid protein (GCDFP)-15 but negative for HER2, were seen in the intracapsular regions. The invasive components consisted of ASCC, which were positive for cytokeratin 5/6 and p63 but negative for AR and GCDFP-15. The SDC and ASCC components were positive for the epidermal growth factor receptor. In both cases, the cytoplasmic localization or decreased expression of E-cadherin was observed in the ASCC. In the early phase, CXPA might emerge as SDC, and it might change into SCC as it invades beyond the capsule due to changes in microenvironment. Also, the aberrant expression of E-cadherin is related to acantholysis in SCC.

Expression of PTEN, Androgen Receptor, HER2/neu, Cytokeratin 5/6, Estrogen Receptor-Beta, HMGA2, and PLAG1 in Salivary Duct Carcinoma

Salivary duct carcinoma (SDC) is an aggressive neoplasm that resembles high-grade invasive ductal carcinoma of the breast. It can develop de novo or from the malignant transformation of pleomorphic adenoma (PA). We performed immunohistochemical stains for phosphatase and tensin homologue [PTEN androgen receptor (AR)], HER2/neu, cytokeratin 5/6, estrogen receptor-beta, high-mobility group AT-hook 2 (HMGA2), and pleomorphic adenoma gene 1 (PLAG1) on tissue microarray samples of 75 SDCs and 31 adenocarcinomas, not otherwise specified (NOS). Our data showed the following in SDC samples: loss of PTEN was found in 17 of 60 (28.3%); AR was expressed in 43 of 62 (69.4%); HER2/neu was overexpressed in 25 of 58 (43.1%); cytokeratin 5/6 was expressed in 14 of 54 (25.9%); estrogen receptor-beta was expressed in 37 of 56 (66.1%); HMGA2 was expressed in 29 of 63 (46.0%); and PLAG1 was expressed in 0 of 62 (0%). In addition, there was no statistically significant difference in the age at onset between patients with HMGA2-positive SDCs (range 32-85 years; mean: 64.3 years; median: 64.5 years) and those with HMGA2-negative SDCs (range 41-79 years; mean: 62.5 years; median: 64.5 years). There was also no statistically significant difference in overall survival between patients with HMGA2-positive and HMGA2-negative SDCs (follow-up period range 3-201 months; mean: 49.8 months; median: 30 months). Among 10 patients with a definite PA component (SDC ex-PA), 6 were positive and 4 were negative for HMGA2. Our data were consistent with previous findings that AR and estrogen receptor-beta are expressed in most SDCs, whereas HER2/neu overexpression and loss of PTEN are expressed in a subset of SDCs. In our cohort of patients, HMGA2 was expressed in approximately half of SDCs. HMGA2 and PTEN are promising therapeutic targets for salivary gland tumors.

Salivary duct carcinoma

PURPOSE OF REVIEW

The review puts new information on geno- and phenotype of salivary duct carcinoma (SDC) in the perspective of the updated 2017 WHO classification.

RECENT FINDINGS

The proportion of SDC is increasing. This may be because of a true rise in incidence, but certainly to better diagnostic tests and changed WHO definitions. In this light, a substantial proportion of carcinoma expleomorphic adenoma is now attributed to the category of SDC. 'Low-grade SDC' and 'SDC in-situ' of the former WHO classification, are now named low-grade and high-grade intraductal carcinoma (IDC), respectively. Recent series quantify biologic aggressiveness: perineural growth, vascular invasion, and extracapsular extension in lymph node metastasis are each observed in two out of three patients with SDC. Most patients die within 3 years, but once 5-year disease-free survival is reached, further disease activity is exceptional. The typical molecular biological profile with high human epidermal growth factor receptor 2 and androgen receptor expression is increasingly successfully exploited in clinical trials for advanced SDC.

SUMMARY

The aggressive SDC is increasingly diagnosed. Despite intensive combined surgery and radiation therapy, many patients recur, for whom new bullets, targeting the molecular biological mechanisms, are the subject of ongoing clinical trials.

Second-Line Treatment of HER2-Positive Salivary Gland Tumor: Ado-Trastuzumab Emtansine (T-DM1) after Progression on Trastuzumab

Patients with salivary duct cancer (SDC) and HER2 overexpression could receive trastuzumab in combination with chemotherapy for metastatic disease. No standard treatment exists for patients with HER2-positive metastatic SDC after progression. We report an excellent patient response to second-line treatment with T-DM1 after progression on paclitaxel plus trastuzumab.

Salivary Duct Carcinoma and Invasive Ductal Carcinoma of the Breast: A Comparative Immunohistochemical Study

Salivary duct carcinoma (SDC) is a high-grade salivary gland malignancy with great morphological resemblance to invasive ductal carcinoma (IDC) of the breast. Rarely, female patients may have a past history of both SDC and IDC. When these patients present with distant metastasis, accurate identification of the primary tumor is particularly difficult. Additionally, rare metastasis of SDC to the breast and IDC to the salivary (parotid) gland can also present a diagnostic challenge. Our aim was to develop an immunohistochemical panel that reliably distinguishes SDC from IDC. We included all SDCs diagnosed from 1989 to 2016 (23 cases) and 29 treatment naïve and histologically similar IDCs. All cases were stained with androgen receptor (AR), estrogen receptor-alpha (ER-α), progesterone receptor (PR), HER-2, CK5/6, p63, and beta-catenin. The great majority (> 90%) of both SDCs and IDCs reacted positively to AR. The main discrepancy in the immunohistochemical profiles was a distinctly different reactivity to ER-α, PR and HER-2. While 28 IDCs (96.6%) reacted positively to ER-α and/or PR, the majority expressing both (82.8%) with a moderate to strong staining intensity, only 2 SDCs expressed ER-α (8.7%) and 5 others expressed PR (21.7%) with only one case expressing both (P value < 0.05). On the other hand, 8 SDC (34.8%) were positive for HER-2 while none of the IDCs were positive (P value < 0.05). ER-α, PR, and HER-2 may be helpful to distinguish SDC from IDC. Positive reactivity to ER-α, PR or both and negative HER-2 favors a diagnosis of IDC while ER-α, PR negative, HER-2 positive tumors are more likely SDC.

HER2/HER3-positive metastatic salivary duct carcinoma in the pleural effusion: A case report

Salivary duct carcinoma (SDC) is an aggressive form of salivary gland tumor, and SDC patients tend to be older men, more commonly in advanced stage with a poorer prognosis. Although the cytological characteristics of SDC on fine-needle aspiration cytology have been well-described at the primary site, they have not been explored in metastasis. Here we reported a case of HER2/HER3-positive metastatic SDC in the lung and pleural effusion. The patient was a man in his 50s who had undergone extended total parotidectomy in 2008. He was originally diagnosed as having HER2-positive left parotid SDC. Six years later a mass was discovered in the left lung by chest computed tomography (CT) and was diagnosed as metastatic SDC by both bronchial biopsy and cytology. Subsequently he had a recurrent SDC in the left pleural effusion and died of respiratory failure. Cytological findings from bronchial brushing smear showed small sheet clusters in a slightly necrotic background. In the pleural effusion cytology, tumor cells appeared as ball-like clusters of epithelioid cells with apocrine-like findings. In immunocytochemistry, HER3 of SDC cells in pleural effusion was significantly overexpressed relative to the matched primary tumor, even though HER2 amplification did not change. Cytological findings and HER family receptors differed between the primary and metastatic SDC. Therefore, molecular tests, such as protein expression and gene amplification using cytological specimens, may become important in future when determining therapy strategies in patients with distant metastasis.

BRCA1/2 Mutations in Salivary Pleomorphic Adenoma and Carcinoma-ex-Pleomorphic Adenoma

Objectives:

It is hypothesized that carcinoma-ex-pleomorphic adenoma (Ca-ex-PA) is malignant from the beginning or is a malignant transformation of a recurrent or a long-standing pleomorphic adenoma (PA). The accumulation of genetic instabilities is suggested to be the main reason for malignant transformation in PA. The aim of this study was to determine the prevalence of BRCA1/2 mutations in PA and Ca-ex-PA.

Materials and Methods:

A total of ninety salivary gland tumors (45 Ca ex-PA and 45 PA) were selected. Immunohistochemistry was performed for all samples. Analyses were conducted through SPSS software version 22.0 (SPSS, Inc., Chicago, IL, USA). Chi-square test was used to examine the differences between the variables. Significant level was set at 0.05.

Results:

In general, 93.3% of PA samples showed positive staining for BRCA1 (in myoepithelial cells); however, BRCA2 positivity was found in 60% of samples (in myoepithelial cells). Among 45 samples of Ca-ex-PA, 93.3% of showed positivity for BRCA1 and 80% of samples showed positivity for BRCA2. Chi-square test found differences between PAs and Ca-ex-PAs regarding BRCA1/2 mutations in ductal cells and myoepithelial cells (P = 0.007, 0.000), respectively.

Conclusions:

The present study found a trend toward the presence of BRCA1/2 mutations in PA and Ca-ex-PA samples. Patients with BRCA1/2 mutation carriers are excellent cases for therapies, such as the poly (ADP) ribose polymerase inhibitor.

Biomarker immunoprofile in salivary duct carcinomas: clinicopathological and prognostic implications with evaluation of the revised classification

Salivary duct carcinoma (SDC) is an uncommon, aggressive malignant neoplasm histologically resembling high-grade mammary ductal carcinoma. SDC can arise de novo or ex pleomorphic adenoma. To clarify the correlation of biomarker immunoprofile with clinicopathological findings and clinical outcome of SDC, we conducted immunohistochemistry for EGFR, HER2, HER3, AR, CK5/6, p53, and Ki-67, along with HER2 fluorescence in situ hybridization in 151 SDCs. SDCs ex pleomorphic adenoma more commonly overexpressed EGFR, HER2, HER3, and Ki-67 than de novo SDCs (P = 0.015, < 0.001, 0.045, and 0.02, respectively). In multivariate analysis, AR− and CK5/6+ were associated with shorter progression-free survival (P = 0.027 and 0.004, respectively). Moreover, patients with p53-extreme negative/positive demonstrated poorer overall survival (P = 0.007). On assessing the revised classification by the combination of biomarker expression, the percentages of each subtype were as follows: ‘apocrine A’ (AR+/HER2−/Ki-67-low) (24%), ‘apocrine B’ (AR+/HER2−/Ki-67-high) (18%), ‘apocrine HER2’ (AR+/HER2+) (35%), ‘HER2-enriched’ (AR−/HER2+) (12%), and ‘double negative’ (AR−/HER2−) (11%). ‘Double negative’ was further subclassified into ‘basal-like’ (EGFR and/or CK5/6+) (7%) and ‘unclassified’ (3%). Consequently, patients with ‘apocrine A’ showed a better progression-free survival than those with any other subtypes. Our revised immunoprofiling classification was valuable for predicting the survival and might be useful in personalized therapy for patients with SDC.

Expression of Hormone Receptors and HER-2 in Benign and Malignant Salivary Gland Tumors

With the advent of targeted therapies, expression of sex hormone receptors and HER-2 in salivary gland tumors (SGTs) is of clinical interest. Previous reports of estrogen (ER) and progesterone (PR) receptor expression have varied. Androgen receptor (AR) and HER-2 overexpression are frequently reported in salivary duct carcinoma (SDC), but have not been studied systematically in other SGTs. This study examines ER, PR, AR, and HER-2 expression in SGTs. Immunohistochemistry for ER, PR, AR, and HER-2 was performed on 254 SGTs (134 malignant). ER, PR, and AR expression was scored using Allred system. HER-2 expression was scored using Dako HercepTest guidelines. FISH for HER-2 amplification was performed on select cases with HER-2 overexpression (2-3+). No SGT demonstrated strong expression of ER or PR. Combined strong AR and HER-2 expression was seen in 22 carcinomas: 14/25 SDC, 3/16 poorly differentiated, two oncocytic, and one each carcinoma ex pleomorphic adenoma, squamous cell, and intraductal carcinoma. Eighteen additional high grade carcinomas had HER-2 overexpression with absent, weak, or moderate AR expression; eight high grade carcinomas had isolated strong AR expression with 0-1+ HER-2 staining. Of 15 tested cases, six demonstrated HER-2 amplification by FISH, all of which had 3+ immunoreactivity. Neither benign nor malignant SGTs had strong expression of ER or PR. None of the benign SGTs overexpressed AR or HER-2. Coexpression of AR and HER-2 should not define SDC, but immunostaining should be considered in high grade salivary carcinomas, as some show overexpression and may benefit from targeted therapy.

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.

Significant and durable clinical benefit from trastuzumab in 2 patients with HER2-amplified salivary gland cancer and a review of the literature

BACKGROUND

Salivary ductal carcinoma and carcinoma ex pleomorphic adenoma (CEPA) are aggressive salivary gland cancers with poor prognosis. The standard of care is resection with or without radiotherapy, and there are no established systemic therapy options.

METHODS

We describe 1 patient with metastatic CEPA and 1 patient with metastatic recurrent salivary duct carcinoma whose tumors were evaluated by comprehensive genomic profiling. Testing identified human epidermal growth factor receptor 2 (HER2) amplification in both patients, and an additional activating HER2 mutation in the CEPA case.

RESULTS

Both patients were treated with the HER2-targeting monoclonal antibody trastuzumab (herceptin) plus chemotherapy and experienced rapid responses. Subsequently, both patients were given single-agent maintenance trastuzumab and continue to experience durable disease control.

CONCLUSION

Given the poor prognosis for salivary gland cancers and the limited treatment options upon recurrence or metastasis, patients should be tested for all classes of HER2 alterations. In cases with HER2 overexpression or activation, targeted therapies, such as trastuzumab are promising. © 2016 Wiley Periodicals, Inc. Head Neck 39: E40-E44, 2017.

Particular aspects in the cytogenetics and molecular biology of salivary gland tumours - current review of reports

Salivary gland tumours are a group of lesions whose heterogeneity of biological and pathological features is widely reflected in the molecular aspect. This is demonstrated by an increasing number of studies in the field of genetics of these tumours.

The aim of this study was to collect the most significant scientific reports on the cytogenetic and molecular data concerning these tumours, which might facilitate the identification of potential biomarkers and therapeutic targets. The analysis covered 71 papers included in the PubMed database. We focused on the most common tumours, such as pleomorphic adenoma, Warthin tumour, mucoepidermoid carcinoma, and others. The aim of this study is to present current knowledge about widely explored genotypic alterations (such as PLAG1 gene in pleomorphic adenoma or MECT1 gene in mucoepidermoid carcinoma), and also about rare markers, like Mena or SOX10 protein, which might also be associated with tumourigenesis and carcinogenesis of these tumours.

Comprehensive Molecular Characterization of Salivary Duct Carcinoma Reveals Actionable Targets and Similarity to Apocrine Breast Cancer

PURPOSE

Salivary duct carcinoma (SDC) is an aggressive salivary malignancy, which is resistant to chemotherapy and has high mortality rates. We investigated the molecular landscape of SDC, focusing on genetic alterations and gene expression profiles.

EXPERIMENTAL DESIGN

We performed whole-exome sequencing, RNA sequencing, and immunohistochemical analyses in 16 SDC tumors and examined selected alterations via targeted sequencing of 410 genes in a second cohort of 15 SDCs.

RESULTS

SDCs harbored a higher mutational burden than many other salivary carcinomas (1.7 mutations/Mb). The most frequent genetic alterations were mutations in TP53 (55%), HRAS (23%), PIK3CA (23%), and amplification of ERBB2 (35%). Most (74%) tumors had alterations in either MAPK (BRAF/HRAS/NF1) genes or ERBB2 Potentially targetable alterations based on supportive clinical evidence were present in 61% of tumors. Androgen receptor (AR) was overexpressed in 75%; several potential resistance mechanisms to androgen deprivation therapy (ADT) were identified, including the AR-V7 splice variant (present in 50%, often at low ratios compared with full-length AR) and FOXA1 mutations (10%). Consensus clustering and pathway analyses in transcriptome data revealed striking similarities between SDC and molecular apocrine breast cancer.

CONCLUSIONS

This study illuminates the landscape of genetic alterations and gene expression programs in SDC, identifying numerous molecular targets and potential determinants of response to AR antagonism. This has relevance for emerging clinical studies of ADT and other targeted therapies in SDC. The similarities between SDC and apocrine breast cancer indicate that clinical data in breast cancer may generate useful hypotheses for SDC. Clin Cancer Res; 22(18); 4623-33. ©2016 AACR.

Salivary duct carcinomas can be classified into luminal androgen receptor-positive, HER2 and basal-like phenotypes

AIMS

The aim of this study was to devise a molecular classification for salivary duct carcinomas (SDCs) based on the similarities between SDCs and breast carcinomas and on characteristics of the microarray-based gene expression profiling-defined molecular subtypes of breast cancer.

METHODS AND RESULTS

Forty-two pure salivary duct carcinomas, 35 of which contained an in-situ component as defined by histological review and/or immunohistochemical analysis, were stained with antibodies for oestrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR) and cytokeratin (CK) 5/6. Based on these markers, tumours were classified into HER2, luminal androgen receptor-positive, basal-like, luminal and indeterminate phenotype. Analysis revealed that 16.7%, 69%, 4.8%, 9.5% and 0% were of HER2, luminal androgen receptor-positive, basal-like, indeterminate and luminal phenotype, respectively. The in-situ and invasive components displayed the same molecular subtype in all but one case.

CONCLUSION

Salivary duct carcinomas can be classified into molecular subgroups approximately equivalent to those in the breast. We also report on the existence of a subgroup of bona fide pure salivary duct carcinomas that have a 'basal-like' phenotype. Understanding the phenotypic complexity of SDCs may help to expedite the identification of novel therapeutic targets for these aggressive tumours.

Biomarker Analysis in Carcinoma ex Pleomorphic Adenoma at an Early Phase of Carcinomatous Transformation

Diagnostic criteria for intracapsular carcinoma ex pleomorphic adenoma (CXPA) are subjective and vary among authors. Biomarker analysis, which could provide more objective evaluation of these tumors, has rarely been studied in intracapsular CXPA. Immunohistochemical evaluation of c-erbB-2, p53 protein, bcl-2, and Ki-67 was performed in 8 cases of CXPA at an early phase of malignant transformation (4 intracapsular and 4 minimally invasive) and in 17 pleomorphic adenomas (PA). In all cases of CXPA, p53 and Ki-67 were demonstrated predominantly in luminal cells of benign and malignant areas, significantly more in the latter. Few benign myoepithelial cells were p53 positive. c-erbB-2 reactivity was strongly associated with atypical luminal cells. Bcl-2 expression was weak and focal in malignant areas from 2 cases. In conclusion, both p53 and c-erbB-2 proteins appear to be involved at an early stage of malignization of PA. In PA with atypical cells, evaluation of the expression of these 2 markers provides more objective criteria for the diagnosis of intracapsular CXPA.

Pathological response of salivary duct carcinoma to trastuzumab and docetaxel therapy

Salivary duct carcinoma (SDC) has a poor prognosis owing to the high incidence of distant metastasis. Approximately 40 % of SDCs are positive for human epidermal growth factor receptor 2 (HER2), suggesting that anti-HER2 therapy for cases with distant metastasis may be effective. However, the pathological response of SDC metastases to anti-HER2 therapy has not been reported. A 44-year-old man was diagnosed with HER2-positive SDC of the submandibular gland with multiple distant metastases. After six cycles of trastuzumab/docetaxel therapy, the patient achieved clinical partial response for the primary tumor and complete response for the neck and distant metastases. Subsequently, the patient underwent submandibular gland resection and neck dissection. On histopathological examination, very few viable cancer cells were identified in the resected primary tumor. Unfortunately, the patient died of multiple distant metastases 12 months after initial treatment. Trastuzumab/docetaxel therapy can elicit a clinical and pathological response in HER2-positive SDC.

Clinical Outcomes and Prognostic Factors for Salivary Duct Carcinoma: A Multi-Institutional Analysis of 141 Patients

BACKGROUND

Among salivary gland malignancies, the prognosis of salivary duct carcinoma (SDC) is assumed to be the poorest. However, because of its low incidence, reliable survival estimates and prognostic factors based on a large number of patients remain to be elucidated, thereby making it impossible to standardize the optimal treatment for SDC.

METHODS

We performed this multi-institutional, retrospective analysis by collecting the clinical information of 141 patients with SDC without distant metastasis who underwent curative surgery as the initial treatment to elucidate overall survival (OS) and disease-free survival (DFS) along with their prognostic factors.

RESULTS

The 3-year OS and DFS rates were 70.5 and 38.2 %, respectively. Multivariate analysis revealed that age ≥65 years (p < 0.001) and N1 and N2 (p = 0.047 and <0.001, respectively) were independent prognostic factors for OS, whereas the primary site of the minor salivary and sublingual gland (p < 0.001) and N2 (p < 0.001) were those for DFS. The most common treatment failure was distant metastasis (55 patients, 39.0 %). For early parotid SDC, neither total parotidectomy in the patients with early T stage nor nerve resection in the patients without facial nerve palsy showed survival benefits.

CONCLUSIONS

Advanced N stage independently affects both OS and DFS. Partial parotidectomy with facial nerve preservation could be a less invasive standard surgical procedure for parotid gland SDC in the early T stage without facial nerve palsy. Effective systemic therapy is imperative to improve DFS of SDC.

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: A clinopathological report of 11 cases

The aim of the present study was to summarize the clinicopathological and immunohistochemical characteristics of salivary duct carcinoma (SDC) and to evaluate the currently available treatment modalities. Between 2001 and 2011, 11 patients with SDC were diagnosed and treated at the Affiliated Hospital of Stomatology of Nanjing University (Nanjing, Jiangsu, China). The present study retrospectively reviewed the clinicopathological and immunohistochemical data of these 11 patients and the results indicated that the parotid gland was the most commonly affected site, followed by the submandibular gland and the palate. Furthermore, the mean age of onset was 58.8 years and all cases were treated with surgery, with 72.7% receiving post-operative radiation therapy. The range for the follow-up period was 10-89 months and of the 11 patients investigated, only two succumbed to the disease. In addition, the two-year overall survival rate was 75% according to Kaplan-Meier analysis and the mean overall survival time was 72.8 months. In conclusion, the present study determined that the site of the malignancy is the best predictor of survival in patients with the rare salivary malignancy SDC, while age, gender, T stage, N stage, American Joint Committee on Cancer stage, nerve paralysis, post-operative radiation, neck dissection, and protein expression levels of Ki-67, androgen receptor and human epidermal growth factor-2/neu are less influential factors.

Carcinoma ex-pleomorphic adenoma of the parotid gland consisting of high-grade salivary duct carcinoma and keratinizing squamous cell carcinoma

Carcinoma ex-pleomorphic adenoma (CXPA) is a rare salivary gland malignancy that presents diagnostic difficulties partly because of its wide range of histologic presentations. We report a case of a 77-year-old man, who presented with a 6-year history of a parotid mass that had undergone rapid growth within weeks. Magnetic resonance imaging revealed an infiltrative mass in the parotid gland, and the fine-needle aspiration (FNA) biopsy result was highly suspicious for carcinoma. Subsequent excision of the tumor demonstrated a poorly differentiated epithelial neoplasm consisting of keratinizing squamous cell carcinoma (SCC) and adenocarcinoma with regions of both ductal carcinoma in situ and invasive salivary duct carcinoma (SDC). Only focal areas exhibited a benign pleomorphic adenoma component. To our knowledge, this is the first case of a CXPA that consists of both a high-grade SDC and a keratinizing SCC in the parotid gland.

Clinicopathologic study of salivary duct carcinoma and the efficacy of androgen deprivation therapy

OBJECTIVE

Salivary duct carcinoma is a rare and aggressive tumor of the salivary glands. The objectives of this study were to investigate the clinicopathological features of salivary duct carcinoma and to determine whether androgen deprivation therapy should be recommended.

STUDY DESIGN AND METHODS

The clinical records of seven patients diagnosed with salivary duct carcinoma between 2002 and 2012 were retrospectively assessed. Tumor specimens were examined for overexpression of human epidermal growth factor receptor 2 (HER2) and androgen receptor by immunohistochemistry. A case of androgen receptor-positive salivary duct carcinoma who received androgen deprivation therapy is presented.

RESULTS

Of the seven patients, 43% had recurrences and metastases, and the 5-year survival rate was 68.6%. All patients were androgen receptor-positive, and 71% were HER2-positive. One patient, a 66-year-old man with androgen receptor-positive salivary duct carcinoma, received oral bicalutimide for 14 months and practically all lung metastases disappeared.

CONCLUSION

Androgen receptor is often overexpressed in salivary duct carcinoma. Androgen deprivation therapy is safe and should be considered for patients with androgen receptor-positive salivary duct carcinoma.

Salivary duct carcinoma and the concept of early carcinoma ex pleomorphic adenoma

AIMS

The data on the histological type of carcinomatous component and the extent of extracapsular invasion for salivary carcinomas ex pleomorphic adenoma (PA) are conflicting. We aimed to determine the prognostic value of extracapsular invasion in salivary duct carcinomas (SDC) ex PA.

METHODS AND RESULTS

A total of 117 patients with SDC were identified retrospectively; 44 cases involving major salivary glands had pre-existing PA (44 of 117, 37%). The morphological spectrum of SDC ex PA was characterized. The primary endpoint was overall survival (OS). Most SDC ex PA were widely invasive at presentation (27 of 44; 61%). Five patients with intracapsular SDC ex PA experienced no disease progression. The assessment of extracapsular invasion was precluded in eight cases (e.g. positive margins of resection). The rate of lymph node involvement was similar in cases with extracapsular invasion of ≤2 mm (two of three) and >7 mm (22 of 26). Only pT correlated with OS [116 months, 95% confidence interval (CI) 22-210 months for pT1 versus 20 months (95% CI 6-34) for pT4; P = 0.013].

CONCLUSIONS

Intracapsular SDC ex PA are potentially indolent. SDC ex PA with extracapsular invasion of ≤2 mm are rare, and appear to be clinically aggressive. Several histological parameters preclude assessment of extracapsular invasion.

Intratumoral heterogeneity of HER2 protein and amplification of HER2 gene in salivary duct carcinoma

Salivary duct carcinoma (SDC) is an aggressive adenocarcinoma of the salivary glands, and accounts for 1-3% of all malignant salivary gland tumors, resembling morphologically invasive ductal carcinoma (IDC) of the breast. In contrast to IDC of the breast and gastric carcinoma (GC), the study of human epidermal growth factor receptor 2 (HER2) in SDC has not progressed. Therefore, we investigated the relationship between HER2 protein expression and amplification of the HER2 gene, and compared them in terms of intratumoral heterogeneity (ITH) in 13 cases of SDC using immunohistochemistry and dual color in situ hybridization. We found seven cases with protein overexpression (53.8%) and five cases with gene amplification (38.5%) in accordance with ASCO/CAP guidelines. ITH of HER2 protein expression was seen in seven cases (53.8%). Interestingly, the ratio of the HER2 gene showed homogenous distribution with or without the presence of ITH of HER2 protein expression. SDC tends to have more ITH of HER2 protein similarly to GC, in contrast to IDC of the breast. ITH of HER2 protein in SDC has no heterogeneity of the HER2 gene amplification. The mechanism of HER2 protein expression in SDC might proceed through a more complex pathway relative to that of IDC of the breast.

Recent advances in the diagnostic pathology of salivary carcinomas

This review concentrates on the most important developments since the WHO classification of 2005. In particular, the identification of specific translocations is revolutionising the way salivary tumours are considered and will have a major impact on future diagnostic practice. This is true so far in four malignancies: mammary analogue secretory, mucoepidermoid, adenoid cystic and hyalinising clear cell carcinomas. In each, the gene rearrangement is found in 80 % or more of cases. Two 2014 publications have added further possible candidates with molecular abnormalities to the list (cribriform adenocarcinoma of the tongue and minor salivary glands and epithelial-myoepithelial carcinoma), but these findings have yet to be confirmed by other investigators. The advances in molecular pathology have also allowed re-evaluation of the morphology; for example, it is now realised that the histological spectrum of hyalinising clear cell carcinoma includes intracellular mucin in over half of cases, as well as tumours with only scanty clear cells. In a separate development, it is now proposed that salivary duct carcinoma can be subdivided along molecular lines, in ways analogous to breast cancer, suggesting new therapeutic prospects in an otherwise highly aggressive malignancy.

[Survival analysis and immunohistochemical study of HER-2 and AR (androgen receptor) expression in salivary duct carcinoma]

BACKGROUND

Because of its low incidence, the clinical characteristics of the salivary duct carcinoma (SDC) based on a statistical analysis with a large number of patients remain to be elucidated, and thus it has been impossible to standardize the optimal treatments of SDC including adjuvant systemic therapy.

AIMS

The present study aimed to determine the prognostic factors along with the clinical outcomes of patients with SDC and to evaluate the expression of several receptor molecules as treatment targets.

METHODS

We performed a statistical analysis and immunohistochemical examination of 16 patients with SDC who had undergone initial treatment in the Department of Otorhinolaryngology, Head and Neck Surgery, Keio University School of Medicine from 1996 to 2010.

RESULTS

The 3-year disease-free survival (DFS) and cause-specific survival (CSS) rates were 29.2% and 72.7%, respectively. At the time of the analysis, 6 patients are alive without the disease, 2 patients are alive with distant metastasis, whereas 7 patients had died of distant metastasis, and 1 patient had died of another cause (pulmonary embolism). We examined the prognostic value of the clinico-pathological factors such as age, sex, T classification, N classification, clinical stage, primary site, histological pre-existence of pleomorphic adenoma. A univariate analysis revealed that DFS was significantly correlated with age (p = 0.049), T classification (p = 0.018), and clinical stage (p = 0.029), whereas no factor was found to be correlated with CSS. A multivariate analysis demonstrated that age (> or = 61 vs. < or = 60, risk ratio (RR) = 5.423, p = 0.042) and T classification (3, 4 vs. 1, 2, RR = 1.087, p = 0.020) were the independent prognostic factors for DFS. Positive expressions of HER2, ER (estrogen receptor), PR (progesterone receptor), AR (androgen receptor), and MIB-1 (index > 20%) were found in 50%, 6%, 13%, 100%, and 69%, respectively. However, none of them showed significant correlation with survival.

CONCLUSION

Frequent expressions of HER-2 and AR in SDC suggest that these receptors can be suitable molecular targets of systemic therapy for patients with SDC in which distant metastasis seems to be the largest obstacle to improving survival. In order to assess the efficacy of anti-HER-2 therapy and anti-androgen therapy for each receptor-positive SDC, a multi-institutional joint research system should be organized.

An immunohistochemical panel for reliable differentiation of salivary duct carcinoma and mucoepidermoid carcinoma

Salivary duct carcinoma is a highly aggressive salivary gland malignancy that may be misdiagnosed as high-grade mucoepidermoid carcinoma. We utilized tissue microarrays with 78 examples of mucoepidermoid carcinoma and 47 salivary duct carcinomas to evaluate the utility of an immunohistochemical panel consisting of androgen receptor, Her2/neu, p63, and cytokeratin 5/6 in distinguishing these entities. Among all cases in the cohorts, androgen receptor was highly specific for salivary duct carcinoma, while cytokeratin 5/6 and p63 were specific for mucoepidermoid carcinoma. While the rate of unequivocal Her2/neu overexpression among the salivary duct carcinomas was low (8.9 %), discrimination of salivary duct carcinoma was enhanced when this marker was used in combination with androgen receptor due to profound sensitivity. The immunohistochemical panel was particularly efficacious at distinguishing the problematic subset of high-grade mucoepidermoid carcinomas from salivary duct carcinoma. Utilization of this set of immunohistochemical markers allows reliable differentiation of salivary duct and mucoepidermoid carcinoma, a distinction with important prognostic and therapeutic implications.

Carcinoma ex pleomorphic adenoma, with particular emphasis on early lesions

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