Gamma radiation sensitivity and risk of malignant and benign salivary gland tumors: a pilot case-control analysis

Survival in Patients with Primary Parotid Gland Carcinoma after Surgery—Results of a Single-Centre Study

This study aims to analyse a single-centre cohort series of patients who underwent parotidectomy for primary malignant parotid tumours. A retrospective chart review of 64 consecutive patients treated from November 2010 to March 2022 was performed. Outcomes were analysed by Kaplan-Meier curves. Sixty-four patients with a primary parotid malignancy were included in the study, with one bilateral case in this cohort. Patients were classified as stage I–II in 39 cases and stage III–IV in 26 cases. The five-year overall survival (OS), disease-specific survival (DSS), local relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were 78.4%, 89%, 92.5%, and 87.1%, respectively. Univariate analysis showed that high-risk histology, stage IV disease, lymphovascular invasion, perineural invasion, node metastasis, skin involvement, facial nerve involvement, and positive or close margins were risk factors associated with poorer outcomes. At present, the best evidence suggests that radical surgery should be the standard approach, and adjuvant therapy, in terms of radiotherapy/chemoradiotherapy, is recommended in patients with risk factors.

Salivary gland neoplasms in non-human primates: A case series and brief literature review

BACKGROUND

Salivary gland neoplasms are rare in non-human primates.

METHODS

Thirty-five years of pathology records were reviewed at the Southwest (SNPRC) and Yerkes (YNPRC) National Primate Research Centers. An in-depth literature search for salivary gland neoplasms in non-human primates was performed.

RESULTS

Seventeen salivary gland neoplasms (nine from SNPRC and YNPRC, eight from published literature) were identified. There were seven malignant, nine benign, and one of undetermined behavior identified in eight rhesus macaques, six baboons, a chimpanzee, a bonnet macaque, and a moustached tamarin. Parotid gland was the most frequent origin (n = 7), followed by mandibular (n = 4) or minor salivary glands (n = 2). Two animals with salivary gland adenoma had a history of prior radiation exposure.

CONCLUSIONS

Parotid glands are the most common origin for salivary gland neoplasms. Salivary gland neoplasms should be considered in the differential diagnoses of head and neck masses in non-human primates.

Prevalence and associated survival of high-risk HPV-related adenoid cystic carcinoma of the salivary glands

Adenoid cystic carcinoma (SACC) is a rare malignancy, but a frequent subtype in minor and major salivary glands. The molecular alterations or biomarkers that underlie its development and progression as well as therapy outcomes are poorly characterized. The main study goal was to investigate reliable biomarkers and patient-related factors that may have impact on recurrence and long-term survival of SACC. The prevalence of human papilloma virus (HPV) in SACC was determined by HPV-DNA genotyping and p16 immunostaining. Epithelial growth factor receptor (EGFR), p53 and Ki-67 expression were also evaluated. Twenty-eight (42%) of 67 patients were HPV-DNA positive. Kaplan-Meier analysis indicated that SACC patients with metastases (P=0.03) had a poor overall survival (OS) and a shorter recurrence-free survival (P<0.001). Positive resection margins significantly predicted shorter recurrence-free survival (P=0.01). In the multivariate analysis, non-metastatic disease (P=0.033) and p16 positivity (P=0.005) have shown their prediction value for OS while non-metastatic disease (P=0.002), HPV positivity (P=0.041) and negative resection margin predicted a better recurrence-free survival. The present study documents for the first time the positivity for HPV infection and overexpression of certain markers (p16, Ki-67, EGFR and p53) used in diagnostics in SACC as well as characterizes clinical entities. These factors might be exploited in the future as biomarkers for its prognostic value. Using the clinical and pathological basis for predicting different outcomes could significantly facilitate SACC stratification and potentially directing treatment.

Functional single-nucleotide polymorphisms in the BRCA1 gene and risk of salivary gland carcinoma

OBJECTIVES

Polymorphic BRCA1 is a vital tumor suppressor gene within the DNA double-strand break repair pathways, but its association with salivary gland carcinoma (SGC) has yet to be investigated.

MATERIALS AND METHODS

In a case-control study of 156 SGC patients and 511 controls, we used unconditional logistical regression analyses to investigate the association between SGC risk and seven common functional single-nucleotide polymorphisms (A1988G, A31875G, C33420T, A33921G, A34356G, T43893C and A55298G) in BRCA1.

RESULTS

T43893C TC/CC genotype was associated with a reduction of SGC risk (adjusted odds ratio=0.55, 95% CI: 0.38-0.80, Bonferroni-adjusted p=0.011), which was more pronounced in women, non-Hispanic whites, and individuals with a family history of cancer in first-degree relatives. The interaction between T43893C and family history of cancer was significant (p=0.009). The GATGGCG and AACAACA haplotypes, both of which carry the T43893C minor allele, were also associated with reduced SGC risk.

CONCLUSION

Our results suggest that polymorphic BRCA1, particularly T43893C polymorphism, may protect against SGC.

Fas single nucleotide polymorphisms and risk of thyroid and salivary gland carcinomas: A case-control analysis

BACKGROUND

The purpose of this study was to examine the association between 4 Fas single nucleotide polymorphisms (SNPs) and risk of differentiated thyroid carcinoma (DTC) and salivary gland carcinoma (SGC).

METHODS

We conducted a case-control study including 279 DTC cases, 165 benign thyroid disease (BTD) cases, 154 SGC cases, 61 benign salivary gland disease (BSGD) cases, and 510 controls.

RESULTS

The A744G SNP genotype distribution was significantly different between subjects with SGC or BSGD and controls, while that of the A18272G SNP was significantly different between subjects with DTC or SGC and controls. Risk of SGC was significantly elevated for the 22628 heterozygous CT genotype (odds ratio [OR] = 1.5, p = .050), and risk of BSGD was elevated for the 22628 homozygous TT genotype (OR = 2.9, p = .023).

CONCLUSION

Fas C22628T SNP may be associated with risk of SGC and BSGD, but none of the investigated Fas SNPs was associated with risk of DTC.

X-ray repair cross-complementing group 1 (XRCC1) single-nucleotide polymorphisms and the risk of salivary gland carcinomas

BACKGROUND

X-ray repair cross complementing group 1 (XRCC1) is important in the repair of single-strand DNA breaks caused by endogenous oxidative species and exogenous carcinogens.

METHODS

This tertiary cancer center-based, case-control association study included 138 patients with salivary gland carcinoma (SGC), 50 patients with benign salivary gland tumors, and a group of 503 cancer-free control participants. Polymerase chain reaction-restriction fragment length polymorphism genotyping assays were performed on 6 XRCC1 single-nucleotide polymorphisms (SNPs). Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated in multivariate logistic regression analyses, and haplotype distributions were estimated.

RESULTS

The XRCC1 genotype distributions of patients with SGC and control participants differed significantly for both the T1915C promoter SNP (P = .047) and the Arg194Trp coding region SNP (P = .037). The polymorphic 1915C allele was significantly less frequent in patients with SGC than in the controls (34% vs 42%; P = .031). Multivariate analysis demonstrated that individuals who had the 1915 polymorphic homozygous CC genotype (OR, 0.4; 95% CI, 0.2-0.9; P = .017) had a significantly lower risk of SGC, and individuals who had the Arg194Trp heterozygous CT genotype (OR, 1.6; 95% CI, 1.0-2.6; P = .059) had a higher, borderline significant risk. The CGTTGG haplotype was associated with a higher SGC risk (OR, 3.5; 95% CI, 1.1-11.3; P = .036). No findings were significant for the patients who had benign salivary gland tumors.

CONCLUSIONS

In this study, the XRCC1 1915C allele was associated with a lower SGC risk, and the XRCC1 194Trp allele was associated with a higher SGC risk.

Evaluation of the p53 tumor suppressor gene mutation in normal rat salivary gland tissue after radioiodine application: an experimental study

In this experimental study, investigators explored p53 tumor suppressor gene mutation induced by low and high doses of iodine-131 sodium iodide (I-131) in salivary gland tissue in rats. Group 1 consisted of 10 rats; low and high I-131 doses were applied at a 1-wk interval. First,low doses of I-131 were injected. (The net injected dose was 47.5-/+9.2 microCi.) After 1 wk, high doses of I-131 were also injected. (The net injected dose was 1007.2-/+53 microCi.) Group 2 consisted of 5 rats, and only a low I-131 dose was applied. (The net injected dose was 52.7-/+5.5 microCi.) The Control Group consisted of 5 rats that did not receive I-131. Thyroidal I-131 uptakes were calculated for Groups 1 and 2 with the use of a gamma camera after 24 h of injections. Immediately after uptake was calculated, salivary glands were resected in all groups and DNA was extracted for genotyping. Genomic DNA of the p53 gene exon 5 was examined by polymerase chain reaction single-strand conformational polymorphism. In Group 1, thyroidal I-131 uptakes were calculated as 12.45%-/+4.14% and 9.66%-/+6.73% after low-dose and high-dose I-131 applications, respectively. In Group 2, thyroidal I-131 uptake was calculated as 13.12%-/+3.04%. In Group 1, p53 gene abnormality was seen in the salivary gland of only 1 of the rats. Double- and single-strand gene profiles showed that both alleles of this rat have a mutated single-strand conformational polymorphism profile of point mutation in the p53 gene exon 5. This rat received the highest low dose and the second highest total dose of I-131; its thyroidal uptakes were the second highest. In the other rats in Group 1, and in Group 2 and the Control Group, p53 gene abnormalities were not observed. In Groups 1 and 2, a significant relationship could not be discerned between thyroidal uptake of I-131 and p53 gene mutation in the salivary gland. No significant relationship was observed between thyroidal uptake alterations and p53 gene mutations in salivary glands in Group 1. A point mutation in the p53 gene exon 5 that was seen in only 1 of the rats in Group 1 seems related to the high-dose application of I-131, although coincidental occurrences could not be excluded. We believe that this topic is open to additional in vivo studies.