Ricardo Hsieh

Instituto de Medicina Tropical de São Paulo · LIM06

Oral mucosal melanomas (OMMs) are aggressive neoplasms commonly found in dogs but rare in humans. Utilizing whole exome sequencing (WES), which focuses on protein-coding regions to reveal mutation profiles, we conducted a comparative analysis of canine OMM and human melanomas. This study involved DNA extraction, exome enrichment, and sequencing fro...

Background Dendritic cells participate in the pathophysiology of lupus erythematosus (LE), which are studied in systemic and cutaneous forms; however, little is known about their oral manifestations. Methods The expressions of dendritic cell markers (including CD1a, CD21, CD123, and langerin) were investigated by immunohistochemistry technique. Si...

Melanomas that arise in sun-protected sites, including acral and oral mucosal melanomas, are likely under the control of unique, specific mechanisms that lead to mutagenesis through various pathways. In this study, we examined somatic mutations in tumors by targeted sequencing using a custom Ion Ampliseq Panel, comprising hotspots of 14 genes that...

Isntroduction Bone invasion is an important prognostic factor in oral squamous cell carcinoma, leading to a lower survival rate and the use of aggressive treatment approaches. Epithelial-mesenchymal transition (EMT) is possibly involved in this process, because it is often related to mechanisms of cell motility and invasiveness. This study examined...

Background: Hair follicles are produced in a cyclical manner and the machinery involved in the reproduction of these follicles is present since the fetal stage. Although extensive research has been done on the human hair follicle, very little is known about the importance of adhesion molecules in its development. Methods: We analyzed here, the immu...

Objective The aim of the present study was to investigate the expression of claudin-1, -3, -4, -5 and -7 proteins in mucoepidermoid carcinoma of oral cavity and analyze whether EGF may interfere in the expression of the genes that encode claudins using in vitro models. Material and Methods Using immunohistochemistry, the expression of claudins was...

Lupus Erythematosus (LE) is a chronic autoimmune inflammatory disease, characterized by a wide spectrum of manifestations of variable evolution. Among the various organs involved, the skin is one of the most frequent site, sometimes being the first manifestation of the disease. The frequency of oral mucosal manifestations is variable, between 9 to...

Introduction: Hair follicles are produced in a cyclical manner and the machinery involved in the reproduction of these follicles is present since the fetal stage. Although extensive research has been done on the human hair follicle, very little is known about the importance of adhesion molecules in its development. Material and methods: We analy...

Primary Oral Mucosal Melanoma represents 0.2 to 8% of all melanomas and 0.5% of all oral malignant neoplasia. The etiology still unknown, however, it has been suggested that head and neck mucosal melanomas change their genetic and metabolic pathways through intracellular cascades, which are associated with its etiopathogenesis mechanisms. The BCL2...

Background The hair follicle is a unique structure, one of the most dynamic structures in mammalians, which can reproduce in every new cycle all the mechanism involved in its fetal development. Although a lot of research has been made about the human hair follicle much less has been discovered about the importance of the cytokeratins (CKs) in its d...

Abstract Background Detection of somatic mutations is a mandatory practice for therapeutic definition in precision oncology. However, somatic mutation detection protocols use DNA from formalin-fixed and paraffin-embedded (FFPE) tumor tissues, which can result in detection of nonreproducible sequence artifacts, especially C:G > T:A transitions, in D...

Objective: The aim of this present review is to provide dentists a better understanding of Primary Sjögren’s syndrome (SSp), clinical and epidemiological findings, also the etiopathogenic and histopathological features of the disease. Methods: The search was based on Pubmed/Medline and ScienceDirect database from 1991 to 2017. It was used keywords:...

Some members of aquaporin family (AQP) plays crucial functions in salivary synthesis and secretion. These proteins expression has already been reported during salivary gland formation, however no previous studies in human developing glands have been performed. We evaluated AQP1, 3 and 5 expression through the stages of human salivary gland morphoge...

Primary oral mucosal melanoma is an extremely rare and aggressive tumor arising from melanocytes located in the mucosal epithelium of the oral cavity. Although malignant melanoma of oral mucosa shares some clinical features with its cutaneous counterpart, it has been associated with a worst prognosis; its etiopathogenesis are still only partially u...

Salivary glands are essential organs that produce and secrete saliva to the oral cavity. During gland morphogenesis, many developmental processes involve a series of coordinated movements and reciprocal interactions between the epithelium and mesenchyme that generate the ductal system and the secretory units. Recent studies have shown new findings...

Graft versus host disease (GVHD) occurs after bone marrow transplantation and is one of the most important causes of death worldwide. Reviews demonstrated GVHD patients with involvement of various tissues and organs, such as salivary glands. The diagnosis of acute GVHD has been the biopsies and the histopathologic evaluation of tissue from an invol...

Primary Sjögren’s syndrome: relevant aspects to dentists • Objective: The aim of this present review is to provide dentists a better understanding of Primary Sjögren’s syndrome (SSp), clinical and epidemiological ndings, also the etiopathogenic and histo- pathological features of the disease. Methods: The search was based on Pubmed/Medline and Scie...

Background : Head and Neck Mucosal Melanoma (HNMM) is rare, accounting 1% of all melanomas in USA, and 6% in Japan. Melanoma’s development is a complex process involving activation of proto-oncogenes and loss of tumor suppressors. Bcl-2 oncogene encodes a family of anti-apoptotic proteins and it is overexpressed in melanomas. On the other hand, pro...

The etiology and pathogenesis of lentiginous acral melanomas are poorly understood. Recent studies have postulated that DNA repair mechanisms and cell growth pathways are involved in the development of melanoma, particularly changes in the MAPK pathways (RAS, BRAF, MEK 1/2, and ERK 1/2). The aim of this study is to assess the status of the MAP kina...

Primary Oral Mucosal Melanoma (POMM) is a very rare entity and it develops from malignant transformation of melanocytes from mucosal epithelium. POMM has a very poor prognosis and aggressive behavior. It represents only 0.5% of all oral malignancies, accounting 0.2 to 8% of all melanomas, with an incidence of 1.2 cases per 10 million per year. POMM...

Objective: The aim of this retrospective study was to identify perineural and vascular invasions in Oral Squamous Cell Carcinoma lesions. Methods: A series of 29 OSSC-diagnosed patients and their clinical and demographic data were collected. In order to identify invasive process, Hematoxiline and Eosin (HE) staining of all cases were analysed and C...

: Head and neck mucosal melanoma (MM) is an aggressive and rare neoplasm of melanocytic origin. To date, few retrospective series and case reports have been reported on MM. This article reviews the current evidence on head and neck MM and the molecular pathways that mediate the pathogenesis of this disease. Head and neck MM accounts for 0.7%-3.8% o...

: Primary oral mucosal melanoma is a rare aggressive tumor. Recent studies have demonstrated a correlation between increased tumor invasion and the metastatic phenotype and altered adhesion molecule expression profiles. The present study analyzed the expression of integrins, claudins, and immunoglobulin-like adhesion molecules in oral mucosal melan...

The etiology and pathogenesis of oral mucosal melanomas are poorly understood, and no intraoral risk factors have been identified. Recent studies have postulated that DNA repair mechanisms and cell growth pathways are involved in the development of melanoma-particularly changes in the CDKN2A (p16-cyclinD-Cdk-pRb) and MAPK pathways (RAS, BRAF, MEK 1...

Oral mucosal melanoma is rare. Its incidence peaks between 41 and 60 years of age; male/female ratio is 2:1. Preferred oral sites include hard palate and maxillary gingiva. Risk factors have not been clearly identified, but pigmented lesions may be present before the diagnosis of oral melanoma. We report an unusual case of oral mucosal melanoma of...

Objective: Primary oral mucosal melanomas are rare, accounting for approximately 2% of all melanomas. The aetiology and pathogenesis of oral mucosal melanomas are poorly understood. Recent studies have reported somatic genetic alterations affecting the mitogen-activated protein kinase (MAPK) signalling pathway in the pathogenesis of cutaneous melan...

Acral lentiginous melanoma (ALM) is a clinicopathologic subtype of cutaneous malignant melanoma. ALM is the most common type of melanoma amongst Asians, Africans, and patients with mixed ancestry. In Brazil, ALM comprises 10% of cutaneous melanoma. ALM develops on palmar, plantar, and subungual skin, and its biology is different from that of other...

FUNDAMENTOS - A deleção e mutação do gene CDKN2a que codifica um inibidor específico da ciclina dependente de quinase 4, a proteína p16, têm sido implicadas na tumorigênese do melanoma cutâneo. Entretanto, pouco se conhece sobre essas alterações genéticas em melanomas de mucosa oral. OBJETIVOS - Verificar a presença de alterações no gene p16 e sua...

BACKGROUND - Deletion and mutation of gene CDKN2a, which encodes a specific inhibitor of cyclin-dependent kinase 4 (CDK4), the protein p16, has been regarded as related to cutaneous melanoma tumorigenesis. However, little is known about those alterations in oral mucosa melanomas. OBJECTIVES - To verify possible p16 gene mutations and its protein ex...