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6
result(s) for
"Amir, Avital L."
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Generating dermatopathology reports from gigapixel whole slide images with HistoGPT
by
Murphree, Dennis H.
,
Mooyaart, Antien L.
,
Lupperger, Valerio
in
14/63
,
631/114/1305
,
631/114/1564
2025
Histopathology is the reference standard for diagnosing the presence and nature of many diseases, including cancer. However, analyzing tissue samples under a microscope and summarizing the findings in a comprehensive pathology report is time-consuming, labor-intensive, and non-standardized. To address this problem, we present HistoGPT, a vision language model that generates pathology reports from a patient’s multiple full-resolution histology images. It is trained on 15,129 whole slide images from 6705 dermatology patients with corresponding pathology reports. The generated reports match the quality of human-written reports for common and homogeneous malignancies, as confirmed by natural language processing metrics and domain expert analysis. We evaluate HistoGPT in an international, multi-center clinical study and show that it can accurately predict tumor subtypes, tumor thickness, and tumor margins in a zero-shot fashion. Our model demonstrates the potential of artificial intelligence to assist pathologists in evaluating, reporting, and understanding routine dermatopathology cases.
Machine learning models represent an opportunity for the automatic generation of histopathology reports. Here, the authors develop HistoGPT, a vision language model that can generate reports from multiple gigapixel-sized whole slide images and also predict tumour thickness, subtypes, and margins, among other diseases.
Journal Article
Mixed T cell receptor dimers harbor potentially harmful neoreactivity
by
Amir, Avital L.
,
van Rood, Johannes J.
,
Hagedoorn, Renate S.
in
Adoptive Transfer
,
Antigens
,
Biological Sciences
2010
Adoptive transfer of T cell receptor (TCR)-transduced T cells may be an attractive strategy to target both hematological malignancies and solid tumors. By introducing a TCR, large numbers of T cells with defined antigen (Ag) specificity can be obtained. However, by introduction of a TCR, mixed TCR dimers can be formed. Besides the decrease in TCR expression of the introduced and endogenous TCR, these mixed TCR dimers could harbor potentially harmful specificities. In this study, we demonstrate that introduction of TCRs resulted in formation of neoreactive mixed TCR dimers, composed of the introduced TCR chains pairing with either the endogenous TCR α or β chain. Neoreactivities observed were HLA class I or class II restricted. Most neoreactive mixed TCR dimers were allo-HLA reactive; however, neoreactive mixed TCR dimers with autoreactive activity were also observed. We demonstrate that inclusion of an extra disulfide bond between the constant domains of the introduced TCR markedly reduced neoreactivity, whereas enhanced effectiveness of the introduced TCR was observed. In conclusion, TCR transfer results in the formation of neoreactive mixed TCR dimers with the potential to generate off-target effects, underlining the importance of searching for techniques to facilitate preferential pairing.
Journal Article
Paired primary and metastatic lesions of patients with ipilimumab-treated melanoma: high variation in lymphocyte infiltration and HLA-ABC expression whereas tumor mutational load is similar and correlates with clinical outcome
2022
BackgroundImmune checkpoint inhibitors (ICI) can lead to long-term responses in patients with metastatic melanoma. Still many patients with melanoma are intrinsically resistant or acquire secondary resistance. Previous studies have used primary or metastatic tumor tissue for biomarker assessment. Especially in melanoma, metastatic lesions are often present at different anatomical sites such as skin, lymph nodes, and visceral organs. The anatomical site may directly affect the tumor microenvironment (TME). To evaluate the impact of tumor evolution on the TME and on ICI treatment outcome, we directly compared paired primary and metastatic melanoma lesions for tumor mutational burden (TMB), HLA-ABC status, and tumor infiltrating lymphocytes (TILs) of patients that received ipilimumab.MethodsTMB was analyzed by sequencing primary and metastatic melanoma lesions using the TruSight Oncology 500 assay. Tumor tissues were subjected to multiplex immunohistochemistry to assess HLA-ABC status and for the detection of TIL subsets (B cells, cytotoxic T cells, helper T cells, and regulatory T cells), by using a machine-learning algorithm.ResultsWhile we observed a very good agreement between TMB of matched primary and metastatic melanoma lesions (intraclass coefficient=0.921), such association was absent for HLA-ABC status, TIL density, and subsets thereof. Interestingly, analyses of different metastatic melanoma lesions within a single patient revealed that TIL density and composition agreed remarkably well, rejecting the hypothesis that the TME of different anatomical sites affects TIL infiltration. Similarly, the HLA-ABC status between different metastatic lesions within patients was also comparable. Furthermore, high TMB, of either primary or metastatic melanoma tissue, directly correlated with response to ipilimumab, whereas lymphocyte density or composition did not. Loss of HLA-ABC in the metastatic lesion correlated to a shorter progression-free survival on ipilimumab.ConclusionsWe confirm the link between TMB and HLA-ABC status and the response to ipilimumab-based immunotherapy in melanoma, but no correlation was found for TIL density, neither in primary nor metastatic lesions. Our finding that TMB between paired primary and metastatic melanoma lesions is highly stable, demonstrates its independency of the time point and location of acquisition. TIL and HLA-ABC status in metastatic lesions of different anatomical sites are highly similar within an individual patient.
Journal Article
Merkel Cell Carcinoma: New Trends
2021
Merkel cell carcinoma (MCC) is a rare neuroendocrine tumor of the skin mainly seen in the elderly. Its incidence is rising due to ageing of the population, increased sun exposure, and the use of immunosuppressive medication. Additionally, with the availability of specific immunohistochemical markers, MCC is easier to recognize. Typically, these tumors are rapidly progressive and behave aggressively, emphasizing the need for early detection and prompt diagnostic work-up and start of treatment. In this review, the tumor biology and immunology, current diagnostic and treatment modalities, as well as new and combined therapies for MCC, are discussed. MCC is a very immunogenic tumor which offers good prospects for immunotherapy. Given its rarity, the aggressiveness, and the frail patient population it concerns, MCC should be managed in close collaboration with an experienced multidisciplinary team.
Journal Article
The association between fetal head position prior to vacuum extraction and pregnancy outcome
2016
Objective
To estimate the association of fetal head position prior to vacuum extraction (VE) and pregnancy outcome.
Study design
A retrospective cohort study of singleton pregnancies who underwent VE. Pregnancy outcome of occipito-anterior (OA) position of the fetal head was compared to those with occipito-posterior (OP) position.
Results
Amongst overall 12,063 women undergoing trial of labor, there were 1118 (9.2 %) VE deliveries. Of them, 871 (77.9 %) had OA and 247 (22.1 %) had OP position of the fetal head. Except for a higher rate of nulliparity in the OA group, no significant differences between the groups regarding pregnancy complications and birthweight were noted. In the OP group, there were higher rates of prolonged 2nd-stage of labor as an indication for VE (49.8 vs. 36.5 %,
p
< 0.001) and single detachment of vacuum cup (11.3 vs. 6.7 %,
p
= 0.02) without any increased risk of failed extraction. Higher risks for sub-galeal hematoma (aOR = 4.36,
p
= 0.03) and low 5-min Apgar score (aOR = 4.63,
p
= 0.02) were observed in the OP group with otherwise similar rates of adverse maternal and neonatal outcomes.
Conclusion
Among women undergoing VE, OP position is associated with higher rate of vacuum cup detachment, low 5-min Apgar score and increased risk for sub-galeal hematoma with otherwise similar rates of adverse maternal and neonatal outcomes.
Journal Article