Translocation-associated salivary gland tumors: a review and update

In recent years the discovery of translocations and the fusion oncogenes that they result in has changed the way diagnoses are made in the salivary gland. These genetic aberrations are recurrent and reproducible and at the very least serve as powerful diagnostic tools in salivary gland diagnosis and salivary gland classification. They also show promise as prognostic markers and hopefully as targets of therapy. Many of these fusions have been found in other tumor types that show little to no overlap with their salivary gland counterparts, but effectively they are specific within the salivary gland. In this review the 5 tumors currently known to harbor translocations will be discussed, namely pleomorphic adenoma, mucoepidermoid carcinoma, adenoid cystic carcinoma, mammary analog secretory carcinoma, and hyalinizing clear cell carcinoma. The discovery and implications of each fusion will be highlighted and how they have helped reshape the current classification of salivary gland tumors.

Temporal nodal regression and regional control after primary radiation therapy for N2-N3 head-and-neck cancer stratified by HPV status

PURPOSE

To compare the temporal lymph node (LN) regression and regional control (RC) after primary chemoradiation therapy/radiation therapy in human papillomavirus-related [HPV(+)] versus human papillomavirus-unrelated [HPV(-)] head-and-neck cancer (HNC).

METHODS AND MATERIALS

All cases of N2-N3 HNC treated with radiation therapy/chemoradiation therapy between 2003 and 2009 were reviewed. Human papillomavirus status was ascertained by p16 staining on all available oropharyngeal cancers. Larynx/hypopharynx cancers were considered HPV(-). Initial radiologic complete nodal response (CR) (≤1.0 cm 8-12 weeks after treatment), ultimate LN resolution, and RC were compared between HPV(+) and HPV(-) HNC. Multivariate analysis identified outcome predictors.

RESULTS

A total of 257 HPV(+) and 236 HPV(-) HNCs were identified. The initial LN size was larger (mean, 2.9 cm vs 2.5 cm; P<.01) with a higher proportion of cystic LNs (38% vs 6%, P<.01) in HPV(+) versus HPV(-) HNC. CR was achieved is 125 HPV(+) HNCs (49%) and 129 HPV(-) HNCs (55%) (P=.18). The mean post treatment largest LN was 36% of the original size in the HPV(+) group and 41% in the HPV(-) group (P<.01). The actuarial LN resolution was similar in the HPV(+) and HPV(-) groups at 12 weeks (42% and 43%, respectively), but it was higher in the HPV(+) group than in the HPV(-) group at 36 weeks (90% vs 77%, P<.01). The median follow-up period was 3.6 years. The 3-year RC rate was higher in the HPV(-) CR cases versus non-CR cases (92% vs 63%, P<.01) but was not different in the HPV(+) CR cases versus non-CR cases (98% vs 92%, P=.14). On multivariate analysis, HPV(+) status predicted ultimate LN resolution (odds ratio, 1.4 [95% confidence interval, 1.1-1.7]; P<.01) and RC (hazard ratio, 0.3 [95% confidence interval 0.2-0.6]; P<.01).

CONCLUSIONS

HPV(+) LNs involute more quickly than HPV(-) LNs but undergo a more prolonged process to eventual CR beyond the time of initial assessment at 8 to 12 weeks after treatment. Post radiation neck dissection is advisable for all non-CR HPV(-)/non-CR N3 HPV(+) cases, but it may be avoided for selected non-CR N2 HPV(+) cases with a significant LN involution if they can undergo continued imaging surveillance. The role of positron emission tomography for response assessment should be investigated.

Lin28b promotes head and neck cancer progression via modulation of the insulin-like growth factor survival pathway

Lin28 is a developmentally regulated RNA binding protein which has recently emerged as key regulator in the biogenesis of the let-7 micro-RNA family. While the expression of Lin28b has been linked to advanced tumor stage, the precise molecular mechanism(s) by which Lin28b drives disease progression is still being unraveled. Herein, we generated a let-7-resistant Lin28b ORF, stably expressed in the FaDu head and neck cancer (HNC) cell line. FaDu-Lin28b cells exhibited enhanced tumor growth in vitro and in vivo. Global gene and micro-RNA expression analyses revealed significant enrichment in several pathways involved in cell migration, chromatin remodeling, and cellular stress response. Direct regulation of selected genes (HMGA2, CCND2, IGF1R, and IGF2BP2) via a let-7-Lin28b mechanism was validated. Notably, up-regulation of several genes in the IGF pathway in Lin28b-expressing cells was observed. Functional studies revealed significant increase in the survival of Lin28b-expressing cells when cultured under stress conditions, which was dependent on the presence of IGF1. Therefore, our data identified several novel gene targets for Lin28b-let7, and revealed a novel mechanism by which Lin28b promote tumorigenesis. Concordantly, clinical examinations of Lin28b, IGF2BP2 and IGF2 revealed a significant association between the expression of these genes with disease relapse, thereby corroborating the potential relevance for the Lin28b/IGF axis in HNC progression.

Intraosseous mucoepidermoid carcinoma: a review of the diagnostic imaging features of four jaw cases

The purpose of this case series is to present the common features of intraosseous mucoepidermoid carcinoma (IMC) of the jaws in plain film and CT imaging. Two oral and maxillofacial radiologists reviewed and characterized the common features of four biopsy-proven cases of IMC in the jaws in plain film and CT imaging obtained from the files of the Department of Oral Radiology, Faculty of Dentistry, University of Toronto, Toronto, Canada. The common features are a well-defined sclerotic periphery, the presence of internal amorphous sclerotic bone and numerous small loculations, lack of septae bordering many of the loculations, and expansion and perforation of the outer cortical plate with extension into surrounding soft tissue. Other characteristics include tooth displacement and root resorption. The four cases of IMC reviewed have common imaging characteristics. All cases share some diagnostic imaging features with other multilocular-appearing entities of the jaws. However, the presence of amorphous sclerotic bone and malignant characteristics can be useful in the differential diagnosis.

Hyalinizing clear cell carcinoma of salivary gland: a review and update

Hyalinizing clear cell carcinoma (HCCC) is a rare minor salivary gland tumor made up of clear cells and forming cords and nests in a hyalinized stroma. The overall outcome is excellent with only occasional metastatic spread. HCCC has a wide differential diagnosis including other clear cell-containing tumors, such as epithelial-myoepithelial carcinoma, mucoepidermoid carcinoma, and myoepithelial carcinoma. HCCC is currently classified as a "clear cell adenocarcinoma" by the AFIP and as "clear cell carcinoma, not otherwise specified (NOS)" by the World Health Organization (WHO). It is considered by the WHO to be a diagnosis of exclusion. Since the original description in 1994, there have been few new insights into HCCC, until recently. Dardick re-examined the features of HCCC, including the original electron microscopic images, and concluded that HCCC is a squamous lesion, at odds with the above nomenclature. Bilodeau et al. recently showed that this tumor essentially cannot be separated reliably from clear cell odontogenic carcinoma (CCOC) except by location. Antonescu et al. recently identified a consistent EWSR1-ATF1 fusion in HCCC. Bilodeau et al. subsequently argued a link between these two entities, with evidence of similar EWSR1 and ATF1 rearrangements in CCOC. This molecular signature is not present in other clear cell mimics. Cases with recurrence, metastasis, high-grade features and other alternative morphologies or presentations have also been seen and proven by molecular analysis to be HCCC. In the molecular era, HCCC can no longer be seen as a diagnosis of exclusion. It is neither an adenocarcinoma nor a "not otherwise specified" tumor, as the AFIP and WHO currently classify it. This review provides an in-depth look at the current state of knowledge of HCCC from morphology to molecular features. New developments and personal insights are provided that help identify and properly classify this lesion.

An analysis of PLAG1 and HMGA2 rearrangements in salivary duct carcinoma and examination of the role of precursor lesions

AIMS

Salivary duct carcinoma (SDC) often arises in pleomorphic adenoma (PA). Putative precursors, including low-grade cribriform cystadenocarcinoma (LGCCC) and ductal carcinoma in-situ (DCIS), are more controversial. Rearrangement of PLAG1 or HMGA2 is seen in 50-70% of PAs, but this has not been investigated in SDC. Using a large collection of SDCs from a single institution, we aimed to study these genes by fluorescence in-situ hybridization (FISH), and to correlate the presence of precursor lesions/intraductal proliferations with gene alterations.

METHODS AND RESULTS

Forty-four SDCs were stained for smooth muscle actin, CK14, and p63, and examined with PLAG1 and HMGA2 FISH. Eight cases were SDC ex-PA; ten had a hyalinized nodule (HN), which is suspicious for PA; six arose in association with LGCCC; and twenty were 'de-novo' SDCs. Ten cases had PLAG1 rearrangement/amplification (22.7%) and eight had HMGA2 (18.2%) rearrangement/amplification. The positive cases were four SDC ex-PAs, eight SDCs with an HN, and five 'de-novo' SDCs. Twenty-three SDC ex-PAs were present in total (52.3%). All six SDC ex-LGCCCs were FISH-negative. Myoepithelial staining surrounded all LGCCCs, and demonstrated DCIS in 17 cases. Eleven DCIS lesions were in SDC ex-PAs or FISH-positive 'de-novo' SDCs. These cases represent 'cancerization' of ducts. Only six FISH-negative 'de-novo' SDCs showed DCIS.

CONCLUSIONS

A large proportion of SDCs arise in PAs (with or without residual evidence of a PA). A small proportion of SDCs arise in LGCCCs. Cases showing DCIS often represent cancerization.

Novel YAP1-TFE3 fusion defines a distinct subset of epithelioid hemangioendothelioma

Conventional epithelioid hemangioendotheliomas (EHE) have a distinctive morphologic appearance and are characterized by a recurrent t(1;3) translocation, resulting in a WWTR1-CAMTA1 fusion gene. We have recently encountered a fusion-negative subset characterized by a somewhat different morphology, including focally well-formed vasoformative features, which was further investigated for recurrent genetic abnormalities. Based on a case showing strong transcription factor E3 (TFE3) immunoreactivity, fluorescence in situ hybridization (FISH) analysis for TFE3 gene rearrangement was applied to the index case as well as to nine additional cases, selected through negative WWTR1-CAMTA1 screening. A control group, including 18 epithelioid hemangiomas, nine pseudomyogenic HE, and three epithelioid angiosarcomas, was also tested. TFE3 gene rearrangement was identified in 10 patients, with equal gender distribution and a mean age of 30 years old. The lesions were located in somatic soft tissue in six cases, lung in three and one in bone. One case with available frozen tissue was tested by RNA sequencing and FusionSeq data analysis to detect novel fusions. A YAP1-TFE3 fusion was thus detected, which was further validated by FISH and reverse transcription polymerase chain reaction (RT-PCR). YAP1 gene rearrangements were then confirmed in seven of the remaining nine TFE3-rearranged EHEs by FISH. No TFE3 structural abnormalities were detected in any of the controls. The TFE3-rearranged EHEs showed similar morphologic features with at least focally, well-formed vascular channels, in addition to a variably solid architecture. All tumors expressed endothelial markers, as well as strong nuclear TFE3. In summary, we are reporting a novel subset of EHE occurring in young adults, showing a distinct phenotype and YAP1-TFE3 fusions.

Frequent PLAG1 gene rearrangements in skin and soft tissue myoepithelioma with ductal differentiation

A subset of cutaneous and superficial soft tissue myoepithelial (ME) tumors displays a distinct ductal component and closely resembles mixed tumors/pleomorphic adenomas of salivary gland. As PLAG1 and HMGA2 rearrangements are the most common genetic events in pleomorphic adenomas, we sought to investigate if these abnormalities are also present in the skin/soft tissue ME lesions. In contrast, half of the deep-seated soft tissue ME tumors lacking ductal differentiation are known to be genetically unrelated, showing EWSR1 rearrangements. FISH analysis to detect PLAG1 and HMGA2 abnormalities was performed in 35 ME tumors, nine skin and 26 soft tissue, lacking EWSR1 and FUS rearrangements. For the PLAG1-rearranged tumors, FISH and RACE were performed to identify potential fusion partners, including CTNNB1 (beta-catenin) on 3p21 and LIFR (leukemia inhibitory factor receptor) on 5p13. Recurrent PLAG1 rearrangement by FISH was detected in 13 (37%) lesions, including three (33%) in the skin and 10 (38%) in the soft tissue. All were classified as benign and all except one showed abundant tubulo-ductal differentiation (comprising 12/24 [50%] of all tumors with ductal structures). A LIFR-PLAG1 fusion was detected by RACE and then confirmed by FISH in one soft tissue ME tumor with tubular formation. No CTNNB1 or LIFR abnormalities were detected in any of the remaining PLAG1-rearranged tumors. No structural HMGA2 abnormalities were detected in any of the 22 ME lesions tested. A subset of cutaneous and soft tissue ME tumors appears genetically linked to their salivary gland counterparts, displaying frequent PLAG1 gene rearrangements and occasionally LIFR-PLAG1 fusion.

Abstract 1949: The identification of potentially prognostic microRNAs in human nasopharyngeal carcinoma

Purpose/Objective:

The majority of nasopharyngeal carcinoma (NPC) patients undergo curative radiation therapy (RT), with concurrent chemotherapy (CT) in cases of locally advanced disease. Current treatments achieve a modest 5-year overall survival rate of ∼70%, underscoring the need for a better understanding of NPC biology in order to develop novel tools to target this disease. In recent years, it has become apparent that micro-RNAs (miRNAs) play important roles in many, if not all human malignancies. Furthermore, miRNAs have been identified whose expression is capable of predicting patient outcome in a variety of human cancers; hence, we proceed to address the primary hypothesis that there is a miRNA expression signature capable of predicting outcome for NPC patients.

Materials/Methods:

The expression level of 734 unique human and viral miRNAs in 121 fully clinically-annotated NPC samples plus 10 normal nasopharyngeal epithelial tissues from healthy individuals was analyzed using the nCounter human microRNA panel from Nanostring®. These data were analyzed in relation to patient clinical and outcomes data (median follow-up time was 6.9 years), in order to identify associations between individual and combinations of miRNAs with clinical parameters.

Results:

Global miRNA expression analyses identified 49 miRNAs which were differentially-expressed between NPC and normal nasopharyngeal epithelial tissues. Using a 2-fold cut-off and Bonferroni correction for multiple comparisons, 39 miRNAs were significantly over-expressed and 10 were significantly under-expressed (miR-145, -216a, -100, -423, -424, -99b, -125a, -125b, -30c, -200a). Additionally, the expression level of 21 miRNAs, appeared to be strongly associate with clinical outcome. Specifically, there were two under-expressed miRNAs which were able to classify patients into low, medium, or high risk groups for distant relapse, wherein their 5-year distant relapse rates were: 0%, 10%, and 36%, respectively; p=0.0006).

Conclusions:

These preliminary data suggest a potential miRNA signature set which can predict for distant relapse, the major cause of death in NPC given the excellent loco-regional control rates with the use of IMRT. Our next step will be to measure the expression level of these 21 candidate miRNAs in an independent validation set of 131 NPC patients to confirm whether any of these miRNAs indeed have prognostic value in NPC. Biological insights will also be acquired by evaluating these miRNAs in pre-clinical NPC models. Prognostic signatures acquired could be used to categorize risk groups, and also facilitate the discovery and development of novel molecularly-targeted therapies which could improve outcome for future NPC patients.

Citation Format: Jeff Bruce, Angela Hui, Daryl Waggot, Bayardo Perez-Ordonez, Ilan Weinreb, Wei Xu, Fei-Fei Liu. The identification of potentially prognostic microRNAs in human nasopharyngeal carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1949. doi:10.1158/1538-7445.AM2013-1949

Outcome predictors in squamous cell carcinoma of the maxillary alveolus and hard palate

OBJECTIVES/HYPOTHESIS

Hard palate and maxillary alveolus are two commonly grouped oral cavity subsites due to their anatomic contiguity and oncologic disease behavior. Few studies have been conducted investigating clinical presentation, staging, prevalence of cervical metastases, and outcomes in this population. The primary objective of this study was to analyze predictors of disease-free survival (DFS) in surgically treated patients, particularly as it relates to the role of neck dissection.

STUDY DESIGN

Cohort study with planned data collection.

METHODS

This cohort study used planned data collection over 15 years (1994-2008) at a large tertiary care cancer center to study all patients presenting with squamous cell carcinoma of the maxillary alveolus and hard palate treated surgically. Univariate and multivariate Cox regression analyses were used to identify predictors of DFS.

RESULTS

Ninety-seven patients met the inclusion criteria (54 male, 56%). The majority of patients (54, 56%) presented with locally advanced disease (cT3, cT4). Occult nodal metastases were noted in 26% (17 of 65) of patients clinically staged as N0. The 3-year DFS was 70% (95% confidence interval = 59%-78%) with a median time to failure of 1.1 years (range = 0.3-9.7 years). Cox regression multivariate model demonstrated that advanced pathologic T stage, hard palate tumor site, and poorly differentiated tumor grade were each independent predictors of DFS.

CONCLUSIONS

A significant portion of the patients with hard palate and maxillary alveolus tumors harbor occult cervical metastases. Elective neck dissection in the high-risk patients may potentially be beneficial in providing more accurate staging and improving DFS.

LEVEL OF EVIDENCE

2b.

What the EWSR1-ATF1 fusion has taught us about hyalinizing clear cell carcinoma

Hyalinizing clear cell carcinoma (HCCC) is a unique low-grade tumor composed of cords and nests of clear cells in a hyalinized stroma that was first reported by Milchgrub et al. It was recognized as a separate entity from clear cell variants of epithelial-myoepithelial carcinoma, myoepithelial carcinoma and mucoepidermoid carcinoma. HCCC is included in a long list of clear cell-containing tumors of salivary gland, as well as odontogenic tumors and metastases (renal cell carcinoma). Up until now, it has been considered a diagnosis of exclusion, despite its very distinctive appearance, and labeled as "not otherwise specified" by the World Health Organization. The emergence of molecular data in salivary gland tumors, including HCCC now allow for a more rigorous appraisal of its spectrum. The EWSR1-ATF1 fusion has proven the concept of a "mucinous HCCC" and removes mucin as an exclusion criterion for this tumor. It has also proven a genetic link between clear cell odontogenic carcinoma and HCCC. Molecularly-proven cases have also highlighted variant morphologies and shown that cases with overt squamous differentiation are true HCCC. This gives further weight to the classification of this tumor as squamous or adenosquamous in differentiation and as a specific entity rather than an "NOS" tumor.

Potentially prognostic miRNAs in HPV-associated oropharyngeal carcinoma

PURPOSE

Deregulation of miRNAs is associated with almost all human malignancies. Human papillomavirus (HPV)-associated oropharyngeal carcinoma (OPC) has a significantly more favorable outcome compared with HPV-negative OPCs; however, the underlying mechanisms are not well understood. Hence, the objectives of this study were to determine whether miRNA expression differed as a function of HPV status and to assess whether such miRNAs provide prognostic value beyond HPV status.

METHODS

Global miRNA profilings were conducted on 88 formalin-fixed and paraffin-embedded (FFPE) OPC biopsies (p16-positive: 56; p16-negative: 32), wherein the expression levels of 365 miRNAs plus 3 endogenous controls were simultaneously measured using quantitative real-time (qRT)-PCR. Seven FFPE specimens of histologically normal tonsils were used as controls.

RESULTS

Overall, 224 miRNAs were expressed in more than 80% of the investigated samples, with 128 (57%) being significantly differentially expressed between tumor versus normal tissues (P < 0.05). Upregulated miR-20b, miR-9, and miR-9* were significantly associated with HPV/p16-status. Three miRNA sets were significantly associated with overall survival (miR-107, miR-151, miR-492; P = 0.0002), disease-free survival (miR-20b, miR-107, miR-151, miR-182, miR-361; P = 0.0001), and distant metastasis (miR-151, miR-152, miR-324-5p, miR-361, miR492; P = 0.0087), which retained significance even after adjusting for p16 status. The associated biologic functions of these miRNAs include immune surveillance, treatment resistance, invasion, and metastasis.

CONCLUSION

We have identified several miRNAs, which associate with HPV status in OPC; furthermore, three candidate prognostic sets of miRNAs seem to correlate with clinical outcome, independent of p16 status. Furthermore, evaluations will offer biologic insights into the mechanisms underlying the differences between HPV-positive versus HPV-negative OPC.

Deintensification candidate subgroups in human papillomavirus-related oropharyngeal cancer according to minimal risk of distant metastasis

PURPOSE

To define human papillomavirus (HPV) -positive oropharyngeal cancers (OPC) suitable for treatment deintensification according to low risk of distant metastasis (DM).

PATIENTS AND METHODS

OPC treated with radiotherapy (RT) or chemoradiotherapy (CRT) from 2001 to 2009 were included. Outcomes were compared for HPV-positive versus HPV-negative patients. Univariate and multivariate analyses identified outcome predictors. Recursive partitioning analysis (RPA) stratified the DM risk.

RESULTS

HPV status was ascertained in 505 (56%) of 899 consecutive OPCs. Median follow-up was 3.9 years. HPV-positive patients (n = 382), compared with HPV-negative patients (n = 123), had higher local (94% v 80%, respectively, at 3 years; P < .01) and regional control (95% v 82%, respectively; P < .01) but similar distant control (DC; 90% v 86%, respectively; P = .53). Multivariate analysis identified that HPV negativity (hazard ratio [HR], 2.9; 95% CI, 2.0 to 5.0), N2b-N3 (HR, 2.9; 95% CI, 1.8 to 4.9), T4 (HR, 1.8; 95% CI, 1.2 to 2.9), and RT alone (HR, 1.8; 95% CI, 1.1 to 2.5) predicted a lower recurrence-free survival (RFS; all P < .01). Smoking pack-years > 10 reduced overall survival (HR, 1.72; 95% CI, 1.1 to 2.7; P = .03) but did not impact RFS (HR, 1.1; 95% CI, 0.7 to 1.9; P = .65). RPA segregated HPV-positive patients into low (T1-3N0-2c; DC, 93%) and high DM risk (N3 or T4; DC, 76%) groups and HPV-negative patients into different low (T1-2N0-2c; DC, 93%) and high DM risk (T3-4N3; DC, 72%) groups. The DC rates for HPV-positive, low-risk N0-2a or less than 10 pack-year N2b patients were similar for RT alone and CRT, but the rate was lower in the N2c subset managed by RT alone (73% v 92% for CRT; P = .02).

CONCLUSION

HPV-positive T1-3N0-2c patients have a low DM risk, but N2c patients from this group have a reduced DC when treated with RT alone and seem less suited for deintensification strategies that omit chemotherapy.

Natural course of distant metastases following radiotherapy or chemoradiotherapy in HPV-related oropharyngeal cancer

OBJECTIVES

To describe the natural course of distant metastases (DMs) following radiotherapy (RT) or chemoradiotherapy (CRT) in HPV(+) oropharyngeal carcinoma (OPC).

METHODS

OPC treated with RT/CRT from 1/1/2000 to 5/31/2010 were reviewed. The natural course of DM were compared between HPV(+) and HPV(-) cohorts.

RESULTS

Median follow-up was 3.9 years. The DM rate were similar (11% vs. 15% at 3-years, p=0.25) between the HPV(+) (n=457) vs. the HPV(-) (n=167) cases. While almost all (24/25) HPV(-) DM occurred within 2-years following RT (1 was at 2.1 years), 7/54 (13%) of HPV(+) DM were detected beyond 3 years (up to 5.3 years). Disseminating to >2 organs occurred in 18 (33%) HPV(+) vs. none in HPV(-). Post-DM survival rates were 11% vs. 4% at 2-years (p=0.02) for the HPV(+) vs. HPV(-) cases respectively. 5/6 HPV(+) with lung oligo-metastasis were still alive with stable disease beyond 2-years after salvage procedures for DM (chemotherapy: 3; surgical resection: 2; radiotherapy: 1).

CONCLUSIONS

Although DM rates are similar, the natural course of HPV(+) DM differs from that of HPV(-) patients: it may occur after a longer interval, often with a "disseminating" phenotype, and a small number may have prolonged survival after salvage for DM.

Equivocal p16 immunostaining in squamous cell carcinoma of the head and neck: staining patterns are suggestive of HPV status

p16 immunohistochemistry (IHC) is commonly used as a surrogate marker for human papillomavirus (HPV) detection in squamous cell carcinomas of the head and neck (SCCHN). However, the HPV status of tumors not staining strongly for p16 is difficult to interpret and may require the use of PCR, not available in all laboratories, as a final arbiter. We aim to determine if staining pattern in equivocal p16 staining and correlation to the percentage of positively stained tumor cells is predictive of HPV status. A retrospective review was performed on all SCCHN that underwent p16 IHC and PCR in our institution from 2007 to 2010. Descriptors of staining pattern in the original IHC report were retrieved. All available IHC slides were reviewed and reclassified using consensus staining pattern descriptors. Original and reclassified descriptors were compared to the final PCR HPV status for statistical significance using the χ(2) test. An estimate of the percentage of tumor cells that showed any form of staining was performed. Thirty-two SCCHN cases that underwent PCR HPV testing had equivocal p16 IHC results. Twenty-six cases available for review were reclassified into four staining patterns. Comparing age, sex, tumor site and diagnosis to HPV PCR status showed no statistically significant findings. However, comparing original descriptors to HPV status was statistically significant with isolated staining associated with negative HPV status (p = 0.0002). Analysis using reclassified descriptors showed strong association of membranous/cytoplasmic staining of isolated cells with negative HPV status and faint, diffuse nuclear and cytoplasmic staining with positive HPV status (p = 0.00006). HPV-negative cases with the former pattern had no more than 30 % positively-stained tumor cells and HPV-positive cases with the latter pattern had 50-90 % positively-stained cells. Our results suggest that pattern of staining in p16 IHC is associated with HPV status. For instance, a diffuse nuclear and cytoplasmic staining pattern, regardless of intensity, is associated with HPV positivity. The HPV-positive cases determined by staining pattern were also associated with a higher percentage of stained tumor cells.

Mammary analog secretory carcinoma of salivary gland origin with the ETV6 gene rearrangement by FISH: expanded morphologic and immunohistochemical spectrum of a recently described entity

Mammary analog secretory carcinoma (MASC) is a recently described tumor predominantly arising in the parotid gland. These tumors represent locally invasive malignancies with microcystic architecture, low-grade nuclei, and granular pink vacuolated cytoplasm. They display strong vimentin and S100 positivity and harbor an identical t(12;15)(p13;q25) to their breast counterpart, leading to a ETV6-NTRK3 fusion oncogene. These features help exclude the most important differential diagnostic considerations, namely, acinic cell carcinoma (AciCC) and low-grade cystadenocarcinoma, not otherwise specified. Here we present a series of 7 recent examples of MASC, which showed features not previously described. These 7 cases were observed in patients ranging in age from 14 to 77 years (mean, 40 y), occurred almost exclusively in male patients (6:1), and showed >50% (4 of 7 cases) involvement of the oral cavity, with only 2 arising in the parotid. The remaining case is the first reported in the submandibular gland. The tumors showed a variety of patterns including single macrocysts, combined macrocystic and microcystic spaces, and solid architecture. They showed prominent hobnailing in the cystic areas. Secretions within the cysts and tubular areas tended to be positive for periodic acid schiff, periodic acid schiff diastage and mucicarmine, the latter also showing occasional intracytoplasmic mucin droplets, a feature not previously recognized. One case showed prominent mucinous differentiation, which, coupled with high-molecular-weight keratins (HMWK) positivity, mimicked mucoepidermoid carcinoma (MEC). The tumors were generally positive for HMWK (6 of 7), S100 (5 of 7), vimentin, CK19, and other epithelial markers. The finding of duct involvement, proven with an incomplete p63-positive basal layer surrounding a minority of tumor cell nests and cysts, raised the possibility of a ductal epithelial origin for MASC. Alternatively, this could represent secondary ductal involvement by tumor. All cases showed rearrangement of the ETV6 gene by fluorescence in situ hybridization, confirming the diagnosis of MASC. These findings reinforce MASC as a unique low-grade salivary gland tumor entity with morphologic overlap with AciCC, MEC, and cystadenocarcinoma.

EWSR1-ATF1 fusion is a novel and consistent finding in hyalinizing clear-cell carcinoma of salivary gland

Hyalinizing clear-cell carcinoma (HCCC) is a rare, low-grade salivary gland tumor with distinctive clear-cell morphology and pattern of hyalinization as well as focal mucinous differentiation. However, histological overlap exists with other salivary gland tumors, such as epithelial-myoepithelial carcinoma (EMCa), salivary myoepithelial carcinoma, and mucoepidermoid carcinoma (MEC). The potential relationship between HCCC and its morphological mimics has not been yet investigated at the genetic level. In this study, we conducted a molecular analysis for the presence of rearrangements in MAML2, commonly seen in MECs, and EWSR1, involved in "soft tissue myoepithelial tumors" (SMET) by fusion with POU5F1, PBX1, or ZNF444. Fluorescence in situ hybridization (FISH) was performed on 23 HCCC cases for abnormalities in MAML2, EWSR1, FUS, POU5F1, PBX1, and ZNF444. FISH for MAML2 was negative in all cases (0 of 14), including those with mucinous differentiation (0 of 7). An EWSR1 rearrangement was identified in 18 of 22 HCCCs (82%), while no break-apart signals were seen in FUS, POU5F1, PBX1, or ZNF444. 3'RACE on an EWSR1 rearranged HCCC identified an EWSR1-ATF1 fusion, which was confirmed by RT-PCR. ATF1 involvement was further confirmed by FISH analysis in 13 of 14 EWSR1-rearranged HCCC cases (93%). In contrast, all control cases tested, including among others 5 EMCa and 3 MEC with clear cells, were negative for EWSR1 and ATF1 rearrangements. The presence of EWSR1-ATF1 fusion in most HCCCs reliably separates these tumors from its histological mimics. The distinction from MEC is particularly important, as conventional MEC grading schemes overgrade these indolent HCCCs, potentially impacting on treatment.

Human papilloma virus: differentiating new primary lung cancer versus metastatic disease from previous head and neck squamous cell carcinoma

Distinguishing new primary lung tumours from lung metastasis in patients with head and neck squamous cell carcinoma (SCC) is a challenging clinical problem. Histological examination is not always able to distinguish between these scenarios as SCC is common in both sites. Here the authors present a case of metachronous cancers of the head and neck and lung in which human papilloma virus testing was proposed as a mechanism to distinguish primary from metastatic carcinoma.