MUC5B levels in submandibular gland saliva of patients treated with radiotherapy for head-and-neck cancer: A pilot study

Abstract

BackgroundThe salivary mucin MUC5B, present in (sero)mucous secretions including submandibular gland (SMG) saliva, plays an important role in the lubrication of the oral mucosa and is thought to be related to the feeling of dry mouth. We investigated if MUC5B levels in SMG saliva could distinguish between the presence or absence of severe dry mouth complaints 12 months after radiotherapy (RT) for head-and-neck cancer (HNC).FindingsTwenty-nine HNC patients with a residual stimulated SMG secretion rate of ≥0.2 ml/10 min at 12 months after RT were analyzed. MUC5B (in U; normalized to 1) and total protein levels (mg/ml) were measured in SMG saliva at baseline and 12 months after RT using ELISA and BCA protein assay, respectively. Overall, median MUC5B levels decreased after RT from 0.12 to 0.03 U (p = 0.47). Patients were dichotomized into none/mild xerostomia (n = 12) and severe xerostomia (n = 17) based on a questionnaire completed at 12 months. SMG and whole saliva flow rates decreased after RT but were comparable in both groups. The median MUC5B level was higher in patients with no or mild xerostomia compared to patients with severe xerostomia (0.14 vs 0.01 U, p = 0.22). Half of the patients with severe xerostomia had no detectable MUC5B at 12 months after RT. No differences in total protein levels were observed.ConclusionsQualitative saliva parameters like MUC5B need further investigation in RT-induced xerostomia. This pilot study showed a trend towards lower MUC5B levels in the SMG saliva of patients with severe xerostomia 12 months after RT for HNC.

Effect of Inhaled Corticosteroids on Salival Composition: A Cross-Sectional Study in Patients with Bronchial Asthma

“…MUC5B plays an important role in the many functions of saliva [15]. Changes in MUC5B concentration have been associated with the appearance of xerostomia in patients subjected to radiotherapy of the head and neck [16] and in patients with Sjögren's syndrome [17]. The present results concur with research previously published by our research team that related the presence of xerostomia to poor clinical management of asthma and high IC use [18].…”

The effect of parotid gland‐sparing intensity‐modulated radiotherapy on salivary composition, flow rate and xerostomia measures

“…Xerostomia measures are reported in three studies (Dijkema et al., ; Randall et al., ; Tiwana et al., ). No studies have undertaken an analysis for a possible relationship between individual saliva components, and physician‐reported (Tiwana et al., ) or patient‐reported (Dijkema et al., ; Randall et al., ) xerostomia scores. We assessed for a possible relationship between PG saliva analytes and xerostomia severity after IMRT.…”

The functions of human saliva: A review sponsored by the World Workshop on Oral Medicine VI

“…30 In addition, a pilot study on 29 patients who had received radiotherapy for head-and-neck cancer showed that the 12 patients with mild or no xerostomia had higher levels of MUC5B in their submandibular saliva than the 17 patients with more severe xerostomia. 31 Thus MUC5B may help to reduce the subjective sensation of xerostomia (dry mouth). However, Yakubov 32 has pointed out that no single component is able to explain the lubricating ability of saliva and that it is likely to be due to a combination of mucins, glycosylated proline-rich proteins and some lower molecular weight proteins.…”