Matteo Fassan - research works

Among 17 CeD patients re-evaluated after a gluten-free diet, all achieved mucosal healing (Marsh 0), 65% showed complete disappearance of deposits, and the remainder a marked reduction.

HER2 expression was 0 in 72.9% of cases, 1+ in 12.1%, 2+ in 8.6%, and 3+ in 6.4%.

HER2 positivity was observed in 9.2% of eCCAs and 9.4% of GBCs.

ERBB2 amplification was consistently identified in all IHC 3+ tumors and in a subset of IHC 2+ and, rarely, 1+ cases.

HER2 expression frequently showed intratumoral heterogeneity, often involving less than 50% of tumor cells.

Tumours containing more than 25% squamous component are classified as gallbladder adenosquamous carcinomas (GBASC), a rare histological subtype characterized by a significantly worse prognosis than conventional adenocarcinomas.

Nearly all tumours (96%) showed PD-L1 positivity with a combined positive score (CPS) greater than 1.

CLDN18.2 expression was identified in 28% of cases, although its confinement to the glandular component may limit its therapeutic applicability.

All tumours were mismatch repair proficient (MMRp), and none demonstrated HER2 overexpression, in contrast to a subset of gallbladder adenocarcinomas.

Loss of BAP1 expression correlated with epithelioid histology and denser T-cell infiltration yet lacked PD-L1 expression.

Aberrant p53 staining was more frequent in spindle-cell tumors, though TP53 mutations were rare, suggesting functional inactivation through other mechanisms.

Notably, mutations typically associated with cutaneous melanomas (e.g., BRAF , KIT , CDKN2A ) were also detected, particularly in a single iris melanoma, suggesting site-specific molecular convergence.

Additional recurrent alterations were found in NOTCH1 , PTEN , PIK3CA , and KDR , implicating the mTOR and VEGF signaling pathways.