Comprehensive Proteomic Analysis Reveals Distinct Features and a Diagnostic Biomarker Panel for Early Pregnancy Loss in Histological Subtypes

Early pregnancy loss (EPL) is a common event in human reproduction and is classified into histological subtypes such as hydropic abortion (HA) and hydatidiform moles, including complete hydatidiform moles (CHMs) and partial hydatidiform moles (PHMs). However, accurate diagnosis and improved patient management remain challenging due to high rates of misdiagnosis and diverse prognostic risks. Therefore, diagnostic biomarkers for EPL are urgently needed. Our study aimed to identify biomarkers for EPL through comprehensive proteomic analysis. Ten CHMs, six PHMs, ten HAs, and 10 normal control products of conception were used to obtain a proteomic portrait. Parallel reaction monitoring–targeted proteomic and regression analyses were used to verify and select the diagnostic signatures. Finally, 14 proteins were selected and a panel of diagnostic classifiers (DLK1, SPTB/COL21A1, and SAR1A) was built to represent the CHM, PHM, and normal control groups (area under the receiver operating characteristic curve = 0.900, 0.804/0.885, and 0.991, respectively). This high diagnostic power was further validated in another independent cohort (n = 148) by immunohistochemistry (n = 120) and Western blot analyses (n = 28). The protein SPTB was selected for further biological behavior experiments in vitro. Our data suggest that SPTB maintains trophoblast cell proliferation, angiogenesis, cell motility, and the cytoskeleton network. This study provides a comprehensive proteomic portrait and identifies potential diagnostic biomarkers. These findings enhance our understanding of EPL pathogenesis and offer novel targets for diagnosis and therapeutic interventions. [Display omitted] •EPL is always highly misdiagnosed in pathology and need biomarkers.•The first comprehensive proteomic characterization of EPL according to histological subtype was provided.•A four-protein (DLK1-SPTB-COL21A1-SAR1A) diagnostic panel was constructed and validated in a larger cohort.•One of selected biomarkers, SPTB, can maintain some trophoblast functions in vitro. Early pregnancy loss is classified into histological subtypes such as hydropic abortion and hydatidiform moles. This is the first proteomic characterization of early pregnancy loss in histological subtypes with a relatively large sample size. Identified numerous proteomic distinctions which revealed the important ways to participate in the pathology of early pregnancy loss. We also developed four-protein classifiers (DLK1, SPTB/COL21A1, SAR1A)