Prognostic Significance of Histopathological Parameters for Salivary Gland Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) is a rare salivary gland tumor that accounts for approximately 1% of all head and neck cancers. Despite its initial indolent behavior, long-term survival is poor due to locoregional recurrence in approximately 40% and distant metastasis in up to 60% of patients who undergo radical treatment. The histological parameters of ACC and the combination of these parameters in histopathological grading systems provide valuable prognostic information about the clinical course of the disease. Within this context, this review aims to analyze the impact of histopathological parameters, individual or combined in histopathological grading systems of malignancy, on ACC prognosis. Individual histopathological parameters such as solid pattern, presence of tumor necrosis, high-grade transformation, dominance of the epithelial component, presence of perineural and lymphovascular invasion, and positive surgical margins have negative impacts on the survival of patients with ACC. There are currently four histopathological grading systems for ACC; however, few studies have validated these systems and most of them explored small cohorts with short follow-up. Considering that the application of grading systems has been associated with ACC prognosis, a broader validation will allow not only their use for prognostic prediction but also assist in treatment planning.

The Combination of Inflammatory Biomarkers as Prognostic Indicator in Salivary Gland Malignancy

Background: The aim of this study was to investigate how the systemic inflammation response index (SIRI), systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR), taken individually and combined, are associated with overall survival (OS) in patients surgically treated for malignant salivary gland tumors (MSGTs). Methods: A retrospective analysis of 74 cases following surgery at our department between January 2011 and June 2018 was performed. The Receiver Operating Characteristic (ROC) curve was used to calculate the optimal cutoff values for SII, SIRI, PLR, and NLR. Survival curves of different groups at 1−3−5 years were estimated using the Kaplan−Meier method. Results: The optimal thresholds with the highest sensitivity and specificity were 3.95 for NLR, 187.6 for PLR, 917.585 for SII, and 2.045 for SIRI. The ROC curves revealed that the best combination with AUC = 0.884 was SII + SIRI. The estimated 5-year OS probability in patients with SII+ SIRI scores of 0, 1, and 2 was 96%, 87.5% and 12.5%, respectively (p < 0.001). Conclusion: SII+ SIRI can independently predict the OS of patients after MSGT surgery. The prognostic score system based on SII+ SIRI may be good clinical practice as a reference for clinical decision-making.

Could Argyrophilic Nucleolar Organizer Regions count mirror DNA Ploidy in Malignant Salivary Gland Tumors?

Objective:

Nucleolar organizer regions (NORs) are DNA coils that transcribe to ribosomal RNA. The NOR-associated protein, termed argyrophilic NOR (AgNOR), was visible within the nucleus by staining with silver nitrate examination via the light microscope. AgNOR counting is a proliferation marker and may help in the diagnosis and prognosis of various neoplastic lesions. Aneuploidy (abnormal DNA content) can predict the progression, survival and prognosis of the tumors. The aim of this study was to evaluate the role of AgNORs, DNA ploidy status, and total S-phase fraction (TSPF) as prognostic parameters in malignant salivary gland tumors (MSGTs).

Methods:

The current study is a retrospective study on a cohort of MSGTs (N=47), to assess AgNORs using Silver Nitrate stain, DNA index (DI), and TSPF using flow cytometry (FCM). Data including tumor size and site, lymphovascular invasion (LVI), lymph node metastasis (LNM) were collected.

Results:

The AgNORs count was statistically significant with MSGT type. DI was found to have a significant association with tumor site, tumor size and MSGT type. In addition, TSPF was found to be significantly associated with LVI. A moderate positive correlation was noted between AgNORs count and TSPF. LNM, tumor site, high AgNORs and low DI were all associated with short disease-free survival (DFS) and poor overall survival (OS).

Conclusion:

The present study revealed that high AgNORs count, DNA aneuploidy and TSPF had a poor influence on MSGTs prognosis.

Overexpression of PD-L2 is associated with shorter relapse-free survival in patients with malignant salivary gland tumors

Objectives

PD-1/PD-L1 and CTLA-4 have been investigated and are thought to play an important role in tumor evasion. This study aimed to investigate expression patterns of immune-related molecules, and their clinical impacts in malignant salivary gland tumors.

Patients and methods

We performed immunohistochemical staining for PD-L1, PD-L2, CTLA-4, PD-1, and CD8⁺ tumor-infiltrating lymphocytes in 70 malignant salivary gland tumors. Protein expression was assessed by H-score by multiplying the staining intensity by the percentage of cells with positive staining.

Results

The tumors comprised mucoepidermoid carcinomas (38.6%), adenoid cystic carcinomas (21.4%), salivary duct carcinomas (15.7%), and others. In malignant salivary gland tumors, PD-L2 expression was high, while expression of PD-L1 was relatively low in terms of the percentage of positively stained cells and the staining intensity. In univariate analysis, PD-L2 expression (H-score <1 vs ≥1), PD-1 (H-score <1 vs ≥1), and CD8⁺ tumor-infiltrating lymphocytes (H-score <1 vs ≥1) were significant prognostic factors. In multivariate analysis, low PD-L2 expression (H-score <1) was independently associated with shorter relapse-free survival (hazard ratio =6.514; 95% confidence interval, 1.2–36.2; P=0.032).

Conclusion

In summary, PD-L2 is potentially an important biomarker in malignant salivary gland tumors, especially in regard to relapse.

Diagnostic dilemma involving a mass in the parapharyngeal space: A metastatic breast carcinoma masquerading as a malignant salivary gland tumor

Parapharyngeal space (PPS) tumors are rare and account for about 0.5% of all head and neck neoplasms. Most PPS tumors are benign (up to 80%) while the remaining 20% are malignant. These tumors are either primaries; most commonly arising from salivary glands or metastatic tumors or due to direct extension of tumors from the adjacent sites. Distant metastasis from breast cancers more commonly involves the lungs, bones, brain and liver. Metastasis to the PPS from a primary breast carcinoma is rare, with only one case reported in literature. We, to the best of our knowledge report the second case of a carcinoma breast metastasizing to the PPS and further discuss the diagnostic and therapeutic challenges involved in its management. A fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography scan apart from explicitly defining the extent of the PPS tumor, majorly influenced the therapeutic decision making process by ruling out other sites of metastasis.

P27/SKP-2 histochemical profile is relevant to malignant salivary gland tumors (MST) histogenesis and tumor grade

Malignant salivary gland tumors (MST) represent over more than 24 distinct morphological subtypes. Most high grade tumors arise from the excretory duct portion of the salivary gland apparatus; the remainder from the intercalated duct portion. Altered p27/skp-2 expression has been associated with tumor aggressiveness and histologic differentiation. In our study, we analyzed p27/skp-2 expression proteins on series of malignant salivary gland tumors in order to assess their value as a histogenetic marker, which is relevant to tumor grade. 61 MST cases were segregated by proposed histogenesis and immunohistochemistry was performed using antibodies directed against p27 and skp-2. MST of proposed intercalated duct origin (n=27) showed strong p27 expression (n=25/27; 93%) in the vast majority of cases and all cases weakly expressed skp-2. MST of proposed excretory duct origin (n=32) showed strong p27 expression (n=18/32; 56%) and moderately strong/strong skp-2 expression (n=18/32; 56%), respectively, in over half the cases. MST of intercalated duct origin showed evident p27/skp-2 inverse correlation. Differences in p27/skp-2 expression among the MST subtypes correlated with histogenesis and tumor grade, which reinforces the notion that tumor behavior is relevant to the portion of the salivary gland unit from which they arise. MST of proposed intercalated duct origin strongly expressed p27, and not skp-2, unlike MST of proposed excretory duct origin. The immunohistochemical profile of high grade mucoepidermoid carcinoma was distinct from its low/intermediate grade counterparts, suggesting a separate identity. These results may influence future decision making when formulating workable MST categorization schemes. Further studies on a larger series of MST are warranted in order to support the value of our findings.

New agents in the treatment for malignancies of the salivary and thyroid glands

The treatment of relatively rare malignancies, such as those of the salivary glands and iodine refractory thyroid cancer, has been invigorated by the development of novel molecular targeting agents. Accrual to clinical trials for these disease sites continues to be limited by their relatively low incidence. Nonetheless, multicenter collaborations have contributed greatly to the development of a number of emerging systemic therapies. This article briefly summarizes the epidemiology and pathogenesis of salivary gland and thyroid cancer, and then describes some of the new drugs under evaluation for these malignancies.