Establishment of homotrimer collagen type I signature and its association with clinical manifestation and tertiary lymphoid structures formation in liver cancer

Background: collagen type I is a fundamental composition of extracellular matrix. Typically it exists in the form of a heterotrimer, consisting of two alpha 1 chains encoded by COL1A1 and one alpha 2 chain encoded by COL1A2. However, in cancer a homotrimeric form of collagen type I comprises three alpha 1 chains encoded by COL1A1 was founded. There is still a lack of transcriptional and histologic methods for detecting homotrimeric collagen type I. Furthermore, a comprehensive analysis of the pan -cancer distribution pattern and clinical relevance of homotrimeric collagen type I is conspicuously absent. Method: Using transcriptional and immunoflourance method, we established homocol signature, which is able to transcriptionally and histologically detect homotrimeric collagen type I. We investigated the diagnostic and prognostic potential of homocol as a novel cancer biomarker in a pan -cancer cohort. Furthermore, we assessed its association with clinical manifestations in a liver cancer cohort undergoing treatment at our institute. Result: Homotrimer Collagen Type I is predominantly expressed by cancer cells and is linked to several critical cancer hallmarks, particularly inflammatory response and proliferation. Survival analyses have indicated that a high Homocol expression is correlated with poor outcomes in most types of cancer studied. In terms of cancer detection, Homocol demonstrated strong performance in Receiver Operating Characteristic (ROC) analysis, with an Area Under Curve (AUC) of 0.83 for pan -cancer detection and between 0.72 and 0.99 for individual cancers.In cohorts undergoing PD1 treatment, we noted a higher presence of Homocol in the response group. In a Hepatocellular Carcinoma (HCC) clinical set, high Homocol expression was associated with an increased formation of intra-tumor tertiary lymphoid structures (TLS), larger tumor sizes, more advanced Barcelona Clinic Liver Cancer (BCLC) stages, higher microvascular invasion (MVI) grades, absence of a capsule, and an enriched para-tumor collagen presence.