Context: Researchers from the Netherlands Cancer Institute have discovered a new location of salivary glands name “tubarial glands”.

About the discovery

• The "accidental" discovery was made when researchers at the Netherlands Cancer Institute were using a combination of CT scans and positron emission tomography (PET) scans called PSMA PET-CT to study prostate cancer.
• They believe, is good news for patients with head and neck tumours as radiation oncologists will be able to bypass this area to avoid any complications during treatment
• Scientists have discovered a new organ: a set of salivary glands set deep in the upper part of the throat. 

Salivary gland System
The salivary gland system in the human body has three paired major glands and over 1,000 minor glands that are spread throughout the mucosa. 
These glands produce saliva necessary for swallowing, digestion, tasting, mastication and dental hygiene. 

Functions of Salivary Gland

• Saliva is a mixture of water, mucus, antibacterial substance, and digestive enzymes. Therefore, saliva has many uses. One of the digestive enzyme alpha-amylase helps to break down the starch present in our food into a simpler one like glucose and maltose. Whenever we chew, we activate these glands to secrete an enzyme to breakdown the food. Saliva has lubricating properties. It protects the inside cavity of our mouth, teeth, and throats as we begin to swallow the food bolus. It also cleanses the mouth after the meal and dissolves it into chemicals that we perceive as taste.

Key Findings

• According to the study, the human throat contains "previously overlooked bilateral macroscopic salivary glands" which the scientists named as "tubarial glands." 
• The researchers examined at least 100 patients to confirm the findings and reported that all of them had the glands. They also dissected the nasopharynx region of two cadavers and found the same results.
• Until now, they thought there were only microscopic salivary glands inside the nasopharynx region behind the nose. However, researchers say this newly found salivary gland organ is likely being used for moistening and lubricating the upper parts of the throat.
• When researchers were studying scans from about 100 people, they found a bilateral structure at the back of the nasopharynx and these glands had characteristics of salivary glands.
• However, Researchers have proposed the name “tubarial glands” for their discovery. Even so, it is not clear yet if these glands will be classified as a conglomerate of minor glands, as a major gland, a separate organ or a new part of an organ system.
• The researchers believe that these glands would qualify as the fourth pair of major salivary glands. The proposed name is based on their anatomical location, the other three glands are called parotid, submandibular and sublingual.

Reason behind delay in discovery of these glands so far

• Researchers note that the location of these glands is at a poorly accessible anatomical location under the base of the skull, which is an area that can only be visualised using nasal endoscopy.
• Further, conventional imaging techniques such as a CT scan, MRI and ultrasound have not allowed the visualisation of these glands. For the scans done on the 100 patients, a new type of scan called the PSMA PET/CT scan was used, which was able to provide the high sensitivity and specificity required to detect these glands.

Purpose of these glands

• So far, researchers suspect that the physiological function of the glands is to moisten and lubricate the nasopharynx and the oropharynx, but this interpretation needs to be confirmed with additional research.

Significance of this finding

• Researchers believe that their discovery is potentially good news for some cancer patients with head and neck cancers. 
• Patients with head and neck cancers and tumours in the tongue or the throat are treated with radiation therapy that can damage the new salivary glands, whose location was not previously known.
• Now, with their discovery, radiation oncologists will be able to circumvent these areas and protect them from the side effects of radiation which can lead to complications such as trouble speaking, swallowing and speaking. 
• Some patients may even face an increased risk of caries and oral infections that can significantly impact their life.
• The major salivary glands whose location is already known are regarded as organs-at-risk while conducting radiation therapy and need to be spared, researchers note.
• “For most patients, it should technically be possible to avoid delivering radiation to this newly discovered location of the salivary gland system in the same way we try to spare known glands,”.

Road Ahead

• The next step is for researchers to find out how to avoid delivering radiation to these newly discovered glands so that patients experience less side effects and lead a better quality of life.