Prognostic markers in salivary gland cancer and their impact on survival

Differential expression of epidermal growth factor receptor in various pathological types of salivary gland cancers

OBJECTIVE

While several studies reported epidermal growth factor receptor (EGFR) expression in salivary gland cancer (SGC), results varied due to a lack of unified definition of EGFR positivity. In this study, we assessed the EGFR expression level using both EGFR positive score and cumulative EGFR score in the patients with SGC.

METHODS

Between January 2010 and April 2021, 102 patients with SGC who underwent surgical resection were reviewed retrospectively by immunohistochemistry. The membrane staining intensity was scored as follows: no staining (0), weak staining (1+), intermediate staining (2+), and strong staining (3+). The cumulative EGFR score was determined on a continuous scale of 0-300 using the formula:1 × (1+: percentage of weakly stained cells) + 2 × (2+: percentage of moderately stained cells) + 3 × (3+: percentage of strongly stained cells).

RESULTS

EGFR expression in SGC varied widely even among the same as well as different histopathological types. The average EGFR positive scores were 46.0 %, 55.7 %, 51.6 %, 1.0 %, 26.8 %, 50 %, and 76.8 % for mucoepidermoid carcinoma (MEC), salivary duct carcinoma (SDC), adenoid cystic carcinoma (AdCC), acinic cell carcinoma (AcCC), adenocarcinoma NOS (ACNOS), carcinoma ex pleomorphic adenoma (CAexPA), and squamous cell carcinoma (SqCC), respectively. The average cumulative EGFR scores were 82, 91, 80, 1, 52, 93, and 185 for MEC, SDC, AdCC, AcCC, ACNOS, CAexPA, and SqCC, respectively.

CONCLUSIONS

EGFR positive scores and cumulative EGFR scores in SGCs varied among the various histological types, and even in the same histological type. These scores may predict the clinical outcome of SGC treated with EGFR-targeting therapies, such as head and neck photoimmunotherapy, and need to be evaluated in future studies.

Molecular Factors in Carcinoma Ex Pleomorphic Adenoma: Systematic Review and Meta-Analysis

OBJECTIVE

Carcinoma ex pleomorphic adenoma (CXPA) is a rare malignant salivary gland tumor. Although multiple reviews have been published on salivary gland malignancies, it has been a decade since the last dedicated systematic review pertaining to CXPA alone was published. This study examines molecular factors in CXPA diagnosis.

DATA SOURCES

MEDLINE, CINAHL, Embase, Scopus, Web of Science (BIOSIS), Cochrane CENTRAL, Health Collection (Informit), OpenDOAR, and GreyNet International.

REVIEW METHODS

Systematic review and meta-analysis from inception to October 31, 2022 for all English language studies pertaining to "carcinoma ex pleomorphic adenoma." Predicted incidence of each biomarker was calculated with meta-analysis. Comparison against pleomorphic adenoma (PA) and salivary duct carcinoma (SDC) when reported within the same study are performed. Risk of bias performed with JBI tool for prevalence studies.

RESULTS

Of 19151 unique studies undergoing abstract screening, 55 studies (n = 1322 patients) underwent data analysis. Biomarkers with >3 studies were p53, HER2, AR, EGFR, PLAG1, ERBB, ER, PR, HMGA2, p16, p63, a-SMA, RAS, PTEN, PDL1, BRAF, PIK3CA, and c-kit. Highest incidence was seen in AR, EGFR, p16, and p53. Significant differences were demonstrated compared with PA and SDC. There was high heterogeneity and overall high risk of bias within studies.

CONCLUSION

Molecular factors are an area of interest in the diagnosis of CXPA. Our study results support examining CXPA as a discrete cohort in future targeted therapy trials. Laryngoscope, 134:1042-1053, 2024.

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.

Contribution of gene polymorphisms on 3p25 to salivary gland carcinoma, ameloblastoma, and odontogenic keratocyst in the Chinese Han population

OBJECTIVE

This study aimed to investigate the contribution of gene polymorphisms in 3p25 to salivary gland carcinoma (SGC), ameloblastoma (AM), and odontogenic keratocyst (OKC) in the Chinese Han population.

STUDY DESIGN

Sixteen tag-single nucleotide polymorphisms (SNPs) within 5 genes (SYN2, TIMP4, PPARG, RAF1, and IQSEC1) in 3p25 were genotyped in 411 individuals with or without SGC, AM, and OKC. Genotype, clinical phenotype, and bioinformatics analyses were performed to evaluate the function of candidate SNPs.

RESULTS

SYN2-rs3773364, TIMP4-rs3755724, PPARG-rs10865710, and PPARG-rs1175544 were related to decreased SGC susceptibility, whereas IQSEC1-rs2600322 and IQSEC1-rs2686742 decreased and increased AM risk, respectively. Stratification analysis revealed that the significance of the identified SNPs was stronger in females or individuals younger than 46 years in SGC. PPARG-rs10865710 and PPARG-rs1175544 were associated with lower lymph node metastasis. SYN2-rs3773364 and PPARG-rs1175544 were associated with favorable SGC patient survival. Functional assessments linked PPARG-rs1175544 to PPARG expression regulation. Linkage disequilibrium analysis revealed a haplotype (SYN2-rs3773364-A, TIMP4-rs3817004-A, and TIMP4-rs3755724-C) associated with decreased susceptibility to SGC. Generalized multifactor dimensionality reduction analysis indicated the gene-gene interactions among IQSEC1, TIMP4, and PPARG in SGC, AM, and OKC progression.

CONCLUSIONS

These variants play important roles in the progression of SGC, AM, and OKC in the Chinese Han population and may be considered biomarkers for early diagnosis and prognosis prediction.

Prognostic role of PD-L1 expression in patients with salivary gland carcinoma: A systematic review and meta-analysis

Background

Although programmed cell death-ligand 1 (PD-L1) has been recognized as a potential marker in several cancers, the relationship between PD-L1 expression and survival in patients with salivary gland carcinoma (SGC) has remained unclear. We aimed to evaluate the association of PD-L1 expression with clinicopathological features and prognosis in SGC patients.

Methods

The databases Ovid Medline, PubMed, Scopus, and EMBASE were searched for relevant studies that detected PD-L1 expression in SGC. The meta-analysis was performed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA), and the reporting recommendations for tumor marker prognostic studies (REMARK) was used to assess the quality of research eligible for this meta-analysis. Included studies were assessed using the Quality in Prognosis Studies (QUIPS) tool. Odds ratios (ORs) with 95% confidence interval (CI) were calculated to estimate the correlation between PD-L1 expression and clinicopathological features. Hazard ratios (HRs) with 95% CI were applied to assess the association between PD-L1 expression and survival outcomes of patients.

Results

A total of ten studies (including 952 patients with SGC) were evaluated. The meta-analysis showed that positive PD-L1 expression in SGC was significantly associated with male patients, older age, Tumor stage, lymph node metastasis, high pathological grade, and non-adenoid cystic carcinoma subtype. The pooled data demonstrated that high PD-L1 expression was associated with poor overall survival and disease-free survival. There was no significant correlation between PD-L1 expression and progression-free survival or disease-specific survival of SGC patients.

Conclusion

According to the meta-analysis, positive PD-L1 expression may play an important role as an effective marker of poor prognosis in patients with SGC. However, large-scale, prospective investigations are still needed to confirm the findings. The assessment of PD-L1 expression may aid in the personalized management of SGC.

Evaluation of HER2/neu expression in different types of salivary gland tumors: a systematic review and meta-analysis

This study is a systematic review and meta-analysis to assess the overexpression rate of HER2 in patients with salivary gland tumors. We included peer-reviewed publications from 1995 to 2020, indexed in medical databases, using search terms such as "human epidermal growth factor receptor 2 (HER2)" and "salivary gland tumors", and extracted relevant data. The extracted data were analyzed with RevMan 5.3 software. Intra-and intergroup post hoc analyses of outcome variables were performed using t-tests, and the rates of HER2 positivity among studies were evaluated. 80 studies were included in the analysis. The positive rates of HER2 ranged from 3.3% to 84.0% and 1% to 9% in malignant and benign subtypes, respectively. The highest HER2 overexpression rate among malignant tumors was in salivary ductal carcinomas (SDC), with a 45% positive rate (CI 95%: 21.9-70.3%). Mucoepidermoid carcinoma (MEC) had the highest positive rate of 84% (CI 95%: 74.1-90.0%). Among benign salivary gland tumors, the highest rate was found in myoepithelioma, with a positive rate of 9% (CI 95%: 1.7-33.6%). The highest rate of HER2 overexpression is present in malignant subtypes of salivary gland tumors, more specifically in salivary ductal carcinoma, mucoepidermoid carcinomas, salivary duct carcinoma in situ, and carcinoma ex pleomorphic adenoma.

Incidence and Prognostic Significance of PD-L1 Expression in High-Grade Salivary Gland Carcinoma

Objective

PD-L1 is one of the predictors of immunotherapy efficacy. Our goal was to analyze its expression and prognostic significance in high-grade salivary gland carcinoma (SGC).

Methods

PD-L1 expression was evaluated using paraffin-embedded specimens from patients with surgically treated high-grade SGC, and it was scored by the tumor proportion score (TPS), combined positive score (CPS), and immune cell (IC) score. Associations between clinicopathological variables, disease-free survival (DFS), overall survival (OS) and PD-L1 expression were assessed.

Results

TPS≥1% occurred in 47 patients with an incidence of 43.1%, and it was significantly related to an advanced tumor stage. In patients with TPS<1%, TPS ranging from 1% to 20%, and TPS≥20%, the 5-year DFS rates were 36%, 26%, and 13%, respectively, and the difference was significant. In patients with TPS<1%, TPS ranging from 1% to 20%, and TPS≥20%, the 5-year OS rates were 49%, 24%, and 13%, respectively, and the difference was significant. CPS≥1 occurred in 87 patients with an incidence of 79.8%. IC scores of 0, 1, 2, and 3 were noted in 24 (22.0%), 37 (33.9%), 31 (28.4%), and 17 (15.6%) patients, respectively. Both CPS and IC scores had no impact on DFS or OS.

Conclusions

The expression of PD-L1 in tumor cells of high-grade SGCs was not uncommon, and it was significantly associated with tumor stage. PD-L1 expression in tumor cells rather than in immune cells indicated a poor prognosis.

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.

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

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

Multicentre, retrospective study of the efficacy and safety of nivolumab for recurrent and metastatic salivary gland carcinoma

Although immune-checkpoint inhibitors (ICIs) are effective against various cancers, little is known regarding their role in salivary gland carcinoma (SGC) treatment. Therefore, we evaluated the efficacy and safety of nivolumab monotherapy in patients with recurrent and/or metastatic SGC. In this multicentre retrospective study, nivolumab (240 mg) was administered every 2 weeks. The overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety were examined; the correlation between treatment outcomes and clinicopathological factors was analysed. Twenty-four patients were enrolled; the most common histopathology was salivary duct carcinoma. Eleven tumours were PD-L1-positive; no tumour was microsatellite instability-high. The ORR was 4.2%, and the median PFS and OS were 1.6 and 10.7 months, respectively. One patient continued nivolumab for 28 months without disease progression. One patient showed grade 4 increase in creatine phosphokinase levels and grade 3 myositis. Biomarker analysis revealed significantly increased OS in patients with performance status of 0; modified Glasgow prognostic score of 0; low neutrophil-to-lymphocyte ratio, lactate dehydrogenase, and C-reactive protein; and high lymphocyte-to-monocyte ratio and in patients who received systemic therapy following nivolumab. Although nivolumab's efficacy against SGC was limited, some patients achieved long-term disease control. Further studies are warranted on ICI use for SGC.

Prognostic Value of Tumor Proportion Score in Salivary Gland Carcinoma

OBJECTIVE

Limited information is available regarding the role of programmed death ligand 1 (PD-L1) expression and CD8⁺ tumor-infiltrating lymphocyte (TIL) density in the tumor immune microenvironment (TIM) of patients with salivary gland carcinoma (SGC). This study aimed to assess the association between the prognosis of SGC patients and the probability of PD-L1 expression in tumor and/or immune cells using the tumor proportion score (TPS), mononuclear immune cell density score (MIDS), combined positive score (CPS), and CD8⁺ TIL density in the TIM.

STUDY DESIGN

Retrospective cohort study.

METHODS

We retrospectively reviewed 73 SGC patients treated with definitive surgery between 2000 and 2015. Immunohistochemical analysis was used to assess TPS, MIDS, CPS, and CD8⁺ TIL density, followed by prognostic evaluation of these immune-related parameters.

RESULTS

Histological grade was associated with TPS, MIDS, and CPS based on PD-L1 expression, and these scores exhibited a significant association with CD8⁺ TIL density. Patients with positive TPS had an unfavorable disease-free survival and overall survival. Multivariate analyses indicated that the TPS was a significant and independent prognostic factor.

CONCLUSION

Our results suggest that TPS might be a useful prognostic biomarker in SGC patients receiving definitive surgery. Laryngoscope, 131:E1481-E1488, 2021.

Prognostic impact of CD8-positive tumour-infiltrating lymphocytes and PD-L1 expression in salivary gland cancer

OBJECTIVES

Aim of the study was to evaluate the prognostic impact of CD8-positive (CD8⁺) tumour-infiltrating lymphocytes (TILs) and PD-L1 expression on the outcome of patients with malignant salivary gland neoplasms.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded tissue samples and clinicopathological data from patients treated for salivary gland carcinoma in a head and neck cancer centre were retrospectively retrieved. Immunohistochemical staining was applied on sections of 84 specimens of 12 different histological subtypes. Both CD8 and PD-L1 expression were rated by semi-automated cell counts by a digital image analysis programme. Survival analyses were performed by the log-rank test on the univariate level, and the Cox model was applied on the multivariate level. Associations between immunological markers and clinicopathological variables were estimated by the Pearson chi-squared test. Additionally, PD-1 was estimated as an exhaustion marker of CD8⁺ TILs.

RESULTS

Patients exceeding a tumour proportion score ≥5% regarding PD-L1 expression demonstrated a significantly decreased survival, as did individuals with an overall high CD8⁺ cell density. Particularly, high CD8⁺ cell counts in the invasive front of the respective tumour tissue significantly coincided with a poor outcome. Also, high numbers of CD8⁺ TILs significantly matched with a high quantity of PD-1⁺ TILs.

CONCLUSION

CD8⁺ TILs abundance in the peritumoural microenvironment correlates with impaired outcome of patients with salivary gland carcinoma. The simultaneous negative prognostic impact of PD-L1 expression and presence of PD-1⁺ TILs advocates an immune checkpoint-controlled mechanism of CD8⁺ TILs exhaustion for these tumours and paves the way for future treatment strategies.

Systemic therapy for metastatic salivary gland tumors—challenges and novel concepts

Salivary gland cancers (SGC) are a rare and heterogeneous group of malignancies. Most frequently tumors arise in the parotid gland. The most common histologic subtypes are adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC). Rare subtypes include salivary ductal carcinoma (SDC), mammary analogue secretory carcinoma (MASC) and adenocarcinoma not other specified (AC NOS). For locally advanced or metastatic disease, chemotherapy has been the mainstay of therapy. The course of disease differs markedly between the subtypes, especially ACC usually presents as slowly progressing disease. Due to the rarity of these tumors only small phase I/II studies exist, which report efficacy of cytotoxic regimens in advanced SGC. However, due to advances in the understanding of tumor biology and molecular testing, drugable genetic changes like androgen receptor (AR) status, HER2/neu overexpression and neurotrophic tyrosine receptor kinase (NTRK) gene fusion have evolved as potential therapy targets in subsets of SGC. Consequently therapy with androgen receptor blockade (ARB) can be offered to patients with AR expressing tumors. Anti-HER2 therapy with trastzumab is an option for the treatment of tumors with overexpression of HER2/neu and finally NTRAK inhibitors can be used for tumors harboring a NTRK gene fusion. Taken together, due to the small number of patients, data from large phase III studies for the treatment of SGC are missing. However, promising targeted therapy approaches have been recently undertaken.