Paulo Freitas Tavares

Dr. Paulo Freitas Tavares

CHUC
orcid

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 1999 in European Journal of Cardio-Thoracic Surgery
Verified
Journal Article
Closed access
MAManuel Antunes
Manuel Antunes
JBJoão Bernardo
João Bernardo
MSMaria Salete
Maria Salete
DPDavid Prieto
David Prieto
LELuis Eugénio
Luis Eugénio
Paulo Freitas TavaresPaulo Freitas Tavares
Paulo Freitas Tavares
The combination of surgery and chemotherapy improves the prognosis of patients with osteogenic sarcoma of the limbs without detectable metastases at presentation. However, lung metastases are a frequent complication. To evaluate the role of the resection of pulmonary metastases of osteogenic sarcoma of the limbs, we have reviewed our experience with this type of surgery, combined with a multidrug chemotherapy protocol. From January 89 to December 97, 198 patients operated on for osteogenic sarcomas of the limbs were followed in our centre. Of these, 31 patients (15.7%), with a mean age of 25 years (range 10-54 years), developed lung metastases and had undergone 45 thoracotomies. All patients received chemotherapy, followed by resection of metastatic lesions and additional chemotherapy. The mean time interval between resection of the primary tumour and the diagnosis of lung metastases was 22 months (4-122 months). Eight patients (25.8%) needed more than one (2-4) thoracotomy. The mean time interval between the first and second thoracic surgeries was 9.2 months (2-14 months). There was no operative mortality or major morbidity. During the 45 thoracotomies, five lobectomies and 40 wedge resections were necessary. The mean number of metastases resected per thoracotomy was 3.4 (range 1-10). The degree of necrosis was evaluated by seriated sections for a histologic study. In the end the mean necrotic volume was calculated. A strong correlation was found between the degree of necrosis of the metastases and the need for reoperation for new metastatic lesions, because all the patients who needed more than one operation had less than 80% of necrosis of metastases. The patients were followed for a mean period of 28 months (6-72 months). Ten patients (32.2%) died of related causes at a mean of 19.4 months after thoracic surgery, three of whom had more than one operation. The 3-year survival after metastasectomy was 61%. Patients without pulmonary metastases had a 3-year survival of 79%. In patients with lung metastases of an osteogenic sarcoma, the combination of chemotherapy and surgery improves the outcome. In our series the mortality was not influenced by the number or thoracotomies required.

2 December 2021 in Cancers
Verified
Journal Article
Open access
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JCJosé Manuel Casanova
José Manuel Casanova
JAJani Sofia Jesus Almeida
Jani Sofia Jesus Almeida
JRJohn David Reith
John David Reith
LSLuana Madalena Sousa
Luana Madalena Sousa
RFRuben Fonseca
Ruben Fonseca
Paulo Rodrigues-SantosPaulo Rodrigues-Santos
Paulo Rodrigues-Santos
Osteosarcoma (OST) is the most common type of high-grade primary bone tumor, which mainly affects young adults. The current standard of care for OST combines surgical resection with chemotherapy. The clinical outcomes and the current options to treat OST patients are unsatisfactory and novel treatment strategies are needed. The crosstalk between tumor cells and immune cells is essential to the OST microenvironment. Despite the efforts that have been made to address the importance of immune-related factors in OST, there is still a lot to understand. The purpose of the current study was to evaluate the tumor-infiltrating lymphocytes (TIL), the expression of proteins involved in tumor biology, and their impact on the clinical outcome of OST patients. We studied 93 samples of OST patients using immunohistochemistry and histomorphometry. We looked for the infiltration of CD3+, CD4+, CD8+, TIA1+ and CD20+ cells and for the expression of CD44 standard (CD44s) and variant 6 (CD44v6), CD95/Fas, Fas-L, p53 and p-glycoprotein. All the parameters were analyzed for the influence on the occurrence of death and metastasis, plus patient overall survival (OS) and progression-free survival (PFS). The effect of sex, age, tumor location (distal femur or proximal tibia) and the combination with neoadjuvant chemotherapy was also assessed. Our results suggest that the presence of tumor-infiltrating CD4+ cells provides protection to OST patients, and that CD8+ cells have a significant impact on the patient’s overall survival (OS) and progression-free survival (PFS), which is more evident in male patients. In addition, a strong association between tumor-infiltrating CD4+ cells and the presence of CD44s expression in tumor samples was observed. Analysis of TIL and tumor markers related to tumor biology could be useful to stratify patients and monitor the response to therapy, as well as to assist with the development of immunotherapy strategies to improve the effects of cytotoxic TIL to eradicate the tumor cells.

4 July 2019 in Scientific Reports
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Journal Article
Open access
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RARaquel Alves
Raquel Alves
AGAna Cristina Gonçalves
Ana Cristina Gonçalves
JJJoana Jorge
Joana Jorge
GMGilberto Marques
Gilberto Marques
DLDino Luís
Dino Luís
ASAna Bela Sarmento-Ribeiro
Ana Bela Sarmento-Ribeiro
MicroRNAs (miRs) dysregulation have emerged as a crucial step in tumorigenesis, being related with cancer development, progression and response to treatment. In chronic myeloid leukaemia (CML), the resistance to tyrosine kinase inhibitors (TKI) is responsible for treatment failure and could be linked to changes in miRs expression. This work aimed to correlate the expression levels of 3 miRs, miR-21, miR-26b and miR-451, with response to TKI treatment in CML patients. miR-451 levels at diagnosis were significantly higher in patients with optimal response after 6 and 12 months of therapy. Conversely, patients without optimal response had highest levels of miR-21. miR-21 and miR-451 appear to be good biomarkers of response, able to predict optimal TKI responders (p < 0.05). Using the combined profile of both miRs, we create a predictive model of optimal response after one year of treatment. This study highlights the role of miR-21 and miR-451 expression levels at diagnosis in predicting which patients achieve the optimal response.

1 March 2013 in The Journal of Foot and Ankle Surgery
Verified
Journal Article
Closed access
CACristina P. Azevedo
Cristina P. Azevedo
JCJosé M. Casanova
José M. Casanova
MGMarta G. Guerra
Marta G. Guerra
ASAntónio L. Santos
António L. Santos
MPMaria I. Portela
Maria I. Portela
Paulo Freitas TavaresPaulo Freitas Tavares
Paulo Freitas Tavares

22 October 2019 in Frontiers in Immunology
Verified
Journal Article
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JAJani Sofia Jesus Almeida
Jani Sofia Jesus Almeida
PCPatrícia Couceiro
Patrícia Couceiro
NLNelson López-Sejas
Nelson López-Sejas
VAVera Alves
Vera Alves
LRLenka Růžičková
Lenka Růžičková
Paulo Rodrigues-SantosPaulo Rodrigues-Santos
Paulo Rodrigues-Santos
Therapy with Tyrosine Kinase Inhibitors (TKI) aiming stable deep molecular response is the gold standard to treat Chronic Myeloid Leukemia (CML). NKT-like cells (CD3+CD56+) combine characteristics of T and NK cells. The physiopathological role of these cells remains unknown although the literature refers their association with inflammation, autoimmune diseases, and cancer. Since the information regarding the role of NKT-like cells in CML is rare, we aimed at the characterization of these cells in CML patients treated with TKIs. Peripheral blood NKT-like cells from 48 CML patients and 40 healthy donors were analyzed by multiparametric flow cytometry. Functional tests consisting of co-culture with leukemic target cells (K562 cell line) were used to measure degranulation and cytokine production. Our results revealed that NKT-like cells are decreased in treated CML patients, although they present increased expression of activation markers (CD69 and HLA-DR), increased degranulation (CD107a) and impaired IFN-γ production. Significantly alterations on the expression of tumor recognition (NCRs and NKp80), and immune regulation receptors (LAG-3, TIM-3, and CD137) by NKT-like cells were observed in CML patients. Second generation TKIs increased cell activation (CD69) and decreased expression of NKp44 and NKp80 by NKT-like cells from CML patients when compared to Imatinib. CML patients that achieved deep molecular response (MR4.5) presented downregulation of NKp44 and LAG-3. Further studies are needed to clarify the role of these cells as biomarkers of therapy response and also to evaluate their value for discrimination of better candidates for sustained treatment-free remission after TKI discontinuation.

1 August 2021 in Cancers
Verified
Journal Article
Open access
PDF file
LSLuana Madalena Sousa
Luana Madalena Sousa
JAJani Sofia Jesus Almeida
Jani Sofia Jesus Almeida
TFTânia Fortes-Andrade
Tânia Fortes-Andrade
MSManuel Santos-Rosa
Manuel Santos-Rosa
Paulo Freitas TavaresPaulo Freitas Tavares
Paulo Freitas Tavares
Paulo Rodrigues-SantosPaulo Rodrigues-Santos
Paulo Rodrigues-Santos
Soft Tissue Sarcomas (STS) are a heterogeneous and rare group of tumors. Immune cells, soluble factors, and immune checkpoints are key elements of the complex tumor microenvironment. Monitoring these elements could be used to predict the outcome of the disease, the response to therapy, and lead to the development of new immunotherapeutic approaches. Tumor-infiltrating B cells, Natural Killer (NK) cells, tumor-associated neutrophils (TANs), and dendritic cells (DCs) were associated with a better outcome. On the contrary, tumor-associated macrophages (TAMs) were correlated with a poor outcome. The evaluation of peripheral blood immunological status in STS could also be important and is still underexplored. The increased lymphocyte-to-monocyte ratio (LMR) and neutrophil-to-lymphocyte ratio (NLR), higher levels of monocytic myeloid-derived suppressor cells (M-MDSCs), and Tim-3 positive CD8 T cells appear to be negative prognostic markers. Meanwhile, NKG2D-positive CD8 T cells were correlated with a better outcome. Some soluble factors, such as cytokines, chemokines, growth factors, and immune checkpoints were associated with the prognosis. Similarly, the expression of immune-related genes in STS was also reviewed. Despite these efforts, only very little is known, and much research is still needed to clarify the role of the immune system in STS.