Salivary gland carcinomas (SGC) are rare tumors. The term SGC is not more than an umbrella for a variety of histogenetically, morphologically, and biologically distinct entities. Accordingly, SGCs have not been sufficiently investigated to date. Their rarity makes it challenging to recruit a high number of patients for individual entities in clinical studies, leading to the pooling of patients with different histological subtypes to achieve sufficient participants. The different histological subtypes of SGC exhibit significant differences in their clinicopathological features, including grading, occurrence, and outcome. SGCs usually are stratified into low-, intermediate-, or high-grade tumors. In most kinds of SGC, specific targetable molecular markers are lacking. The inclusion of immunotherapy (IT), however, might improve the outcome of patients suffering from high-grade SGCs. To integrate IT as a therapeutic option for SGC and to facilitate informed therapeutic decisions based on tumor (immune) biology, predictive and prognostic immunological biomarkers are indispensable. In this prospective study, 500 patients will be enrolled, distributed across three arms. The observational cohort includes patients with malignant salivary gland tumors, whereas patients with benign tumors of a salivary gland are grouped in the control group 1. In the control cohort, two patients do not have a salivary gland tumor but have a planned functional surgery of the nose or ear or a maxillofacial surgery. The local immune status of the tumor tissue and the microbiome will be sampled before treatment. In addition, the systemic immune status from peripheral blood will be analyzed before and after surgery and after the adjuvant and definitive chemoradiotherapy (CRT), if applicable. Clinical baseline characteristics and outcome parameters will additionally be collected. Data mining and modeling approaches will be applied to identify interactions between local and systemic immune parameters and to define predictive and prognostic immune signatures based on the evaluated immune markers.

Inclusion Criteria:

1. Observational group

   • Initial diagnosis of a primary salivary gland carcinoma in the head and neck region (no squamous cell carcinomas)
   • Specimen collection from the center of the tumor when the primary tumor is sufficiently large without that the pathological assessment is impaired

2. Control group 1

   • Initial diagnosis of a benign salivary gland tumor in the head and neck region
   • Specimen collection from the center of the tumor when the primary tumor is sufficiently large without that the pathological assessment is impaired

3. Control group 2

   • functional diseases of the nose or ear (patients with the indication for functional ear surgery and rhinoplasty)
   • Specimen collection with sufficiently large resectate during a functional nose surgery

for all groups:

• Willingness of patients to collect blood, saliva and stool and consent to the preservation of all samples for study purposes.
• Age ≥ 18 years
• sufficient cognitive ability of the patients to understand the purpose of the study and to understand the purpose of the study and agree to it

Exclusion Criteria:

• Distant metastasis at the time of diagnosis and simultaneous second cancers, i.e. at study inclusion
• Malignancy in the last 5 years regardless of location (except basal cell carcinoma or cis of the uterine cervix)
• Carcinomas for which specimen collection is not possible or likely without compromising the compromise the pathological evaluation
• Persistent drug or medication abuse
• Patients who are unable or unwilling to comply with protocol and to be treated
• Patients who are represented by a legal guardian
• Patients who are not suitable for participation in the study due to a language barrier

Patients presenting for treatment at the participating study centers and meeting the inclusion criteria.