Tumor immune microenvironment in adenoid cystic carcinoma of the lacrimal gland: relationship with histopathology and prognosis.

Abstract

Purpose: To quantitatively investigate the pathological subtypes of lacrimal gland adenoid cystic carcinoma (LGACCs), the tumor immune microenvironment in each pathological subtype, and the relation to survival.

Methods: In this retrospective study, the tumor subtype was determined by H&E staining. Multiplex immunochemistry was performed to define specific immune cells. The tumor immune microenvironment (TIME) was sketched by sequential image scanning and reconstructed by a cytometry platform.

Results: Eighteen patients with adequate paraffin blocks diagnosed with LGACC from 2012 to 2021 were included in this study. Thirteen patients out of the eighteen patients (72.2%)showed a mixture of different pathological subtypes. Each pathological subtype took different percentages on different tumors. The cribriform was the most common subtype, taking an overall percentage of 39%. The rest of the pathological subtypes were tubular (19%), basaloid (17%), cribriform and tubular mixture (C + T) 14%. The sclerosing and comedocarcinomic subtypes were the least seen in LGACC, taking a percentage of 11% altogether. Patients with cribriform dominant component had better overall survival than the non-cribriform dominant patients. Patients with basaloid dominant component had worse clinical outcomes than the non-basaloid dominant ones. The TIME showed high immunogenicity in the tumor margin but declined in the tumor areas. Pathological subtypes rather than individual differences determined the TIME phenotype. The cribriform subtype possessed more immune cell infiltration than other pathological subtypes.

Conclusions: LGACC is composed of multiple pathological subtypes. Each pathological subtype takes different percentages on different tumors, which is related to the prognosis. TIME pattern in LGACC varies among different pathological subtypes, which could indicate novel strategies in immunotherapy.