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Ito T, Tanaka Y, Murata M, Kaku-Ito Y, Furue K, Furue M. BRAF Heterogeneity in Melanoma. Curr Treat Options Oncol 2021; 22:20. [PMID: 33558987 DOI: 10.1007/s11864-021-00818-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2021] [Indexed: 01/19/2023]
Abstract
OPINION STATEMENT In the era of molecular targeted therapy, the accurate detection of BRAF mutation in melanoma has become increasingly important. With the advances of molecular analyses and immunohistochemistry, the presence of BRAF mutational heterogeneity in melanoma has been widely recognized. Although most patients with melanoma have a homogeneous BRAF mutation status because the BRAF mutation occurs at an early stage of melanoma development and acts as a driver gene mutation, BRAF mutational heterogeneity does exist, among different tumor sites of a single patient (intertumor heterogeneity) and/or even within a single tumor (intratumor heterogeneity). To summarize the published reports, about 10% of melanoma patients may show intertumorally discordant BRAF status and about 15% of BRAF-mutated melanomas may have intratumor BRAF heterogeneity, although the reported results vary strikingly among the studies and methods used. Considering the BRAF heterogeneity of melanoma, a single biopsy from a single tumor may not be sufficient to uncover the entire BRAF status of a patient. Multiple samples from different sites may be preferable to assess the indication of BRAF/MEK inhibitors, as recommended by the current clinical guidelines. The impact of BRAF heterogeneity on patient survival or the response to treatment with BRAF/MEK inhibitors is an interesting issue, but requires further investigation.
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Affiliation(s)
- Takamichi Ito
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka, 812-8582, Japan.
| | - Yuka Tanaka
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka, 812-8582, Japan
| | - Maho Murata
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka, 812-8582, Japan
| | - Yumiko Kaku-Ito
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka, 812-8582, Japan
| | - Kazuhisa Furue
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka, 812-8582, Japan
| | - Masutaka Furue
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashiku, Fukuoka, 812-8582, Japan
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Comodo-Navarro AN, Fernandes M, Barcelos D, Carapeto FCL, Guimarães DP, de Sousa Moraes L, Cerutti J, Iwamura ESM, Landman G. Intratumor Heterogeneity of KIT Gene Mutations in Acral Lentiginous Melanoma. Am J Dermatopathol 2020; 42:265-271. [PMID: 31393283 DOI: 10.1097/dad.0000000000001475] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Melanoma is an aggressive skin malignancy, and the acral lentiginous melanoma (ALM) subtype affects non-sun-exposed sites such as the volar surface of the hands and feet and the subungual region and is most common in Asians, Hispanics, and Afro-descendants. The presence of different clones within the same tumor seems to influence the aggressiveness of tumors. Patients with mutations in the KIT gene have shown a good response to tyrosine kinase inhibitor therapy. We tested the hypothesis of intratumor heterogeneity through analysis of KIT gene mutations in ALM and determined the correlation between KIT mutations and demographic, clinical, and histopathological variables. Twenty-five ALM samples were examined. We selected up to four different regions per tumor for sequencing by the Sanger method for analysis of KIT gene exon 11 and exon 13 mutations. Advanced lesions were predominant, and the main histopathological characteristics of lesions were Breslow index >4.0 mm (17/25, 68%), Clark level IV/V (21/25, 84%), ulceration (16/25, 64%), and >3 mitoses/mm (8/25, 32%). KIT gene mutations were detected in 11/25 cases (44%), and all these 11 cases displayed intratumor heterogeneity, that is, at least 2 tumor regions had different mutational profiles. The predicted effect of most mutations detected was detrimental to protein function. No significant correlations between histopathological variables and either KIT mutations or intratumor heterogeneity were observed. The hypothesis of intratumor heterogeneity of KIT gene mutations in acral lentiginous melanoma was supported.
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Affiliation(s)
| | - Mariana Fernandes
- Departamento de Patologia, Universidade Federal de São Paulo, São Paulo, Brazil; and
| | - Denise Barcelos
- Departamento de Patologia, Universidade Federal de São Paulo, São Paulo, Brazil; and
| | | | | | - Lais de Sousa Moraes
- Departamento de Morfologia e Genética, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Janete Cerutti
- Departamento de Morfologia e Genética, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Gilles Landman
- Departamento de Patologia, Universidade Federal de São Paulo, São Paulo, Brazil; and
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Keppeke GD, Barcelos D, Fernandes M, Comodo AN, Guimarães DP, Cardili L, Carapeto FCL, Andrade LEC, Landman G. IMP dehydrogenase rod/ring structures in acral melanomas. Pigment Cell Melanoma Res 2020; 33:490-497. [PMID: 31883196 DOI: 10.1111/pcmr.12854] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 12/24/2022]
Abstract
Acral lentiginous melanoma (ALM) is a rare subtype of melanoma with aggressive behavior. IMPDH enzyme, involved in de novo GTP biosynthesis, has been reported to assemble into large filamentary structures called rods/rings (RR) or cytoophidium (cellular snakes). RR assembly induces a hyperactive state in IMPDH, usually to supply a high demand for GTP nucleotides, such as in highly proliferative cells. We investigate whether aggressive melanoma tumor cells present IMPDH-based RR structures. Forty-five ALM paraffin-embedded tissue samples and 59 melanocytic nevi were probed with anti-IMPDH2 antibody. Both the rod- and ring-shaped RR could be observed, with higher frequency in ALM. ROC curve analyzing the proportions of RR-positive cells in ALM versus nevi yielded a 0.88 AUC. Using the cutoff of 5.5% RR-positive cells, there was a sensitivity of 80% and specificity of 85% for ALM diagnosis. In ALM, 36 (80%) showed RR frequency above the cutoff, being classified as RR-positive, compared with only 9 (15%) of the nevi (p < .001). Histopathology showed that 71% of the RR-positive specimens presented Breslow thickness > 4.0mm, compared with only 29% in the RR-low/negative (p = .039). We propose that screening for RR structures in biopsy specimens may be a valuable tool helping differentiate ALM from nevi and accessing tumor malignancy.
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Affiliation(s)
- Gerson D Keppeke
- Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Denise Barcelos
- Department of Pathology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Mariana Fernandes
- Department of Pathology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Andréia N Comodo
- Department of Pathology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Daiane P Guimarães
- Department of Pathology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Leonardo Cardili
- Department of Pathology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Fernando C L Carapeto
- Department of Pathology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Luis E C Andrade
- Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Gilles Landman
- Department of Pathology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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Fernandes M, Barcelos D, Comodo AN, Guimarães DP, Lopes Carapeto FC, Cardili L, de Sousa Morães L, Cerutti Ap J, Landman Ap G. Acral Lentiginous Melanomas Harbour Intratumor Heterogeneity in BRAF Exon 15, With Mutations Distinct From V600E/V600K. Am J Dermatopathol 2019; 41:733-740. [PMID: 31021835 DOI: 10.1097/dad.0000000000001418] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The choice of appropriate therapeutic strategies may be influenced by intratumor heterogeneity and makes cancer treatment considerably more challenging. We aimed to evaluate the heterogeneity of BRAF exon 15 mutations in different areas of acral lentiginous melanoma (ALM). The entire exon 15 was sequenced in 4 different areas of paraffin-embedded samples from 26 patients with ALM. A total of 26 of 49 cases of ≥1 mm in depth of ALM identified by clinical, anatomical, and pathological data fulfilled the inclusion and exclusion criteria for this study. Tumors had a mean Breslow depth of 7.2 mm and an average mitotic index of 3 mitosis/mm. Mutations distinct from the common V600E and V600K were detected in 31%, and intratumor heterogeneity was observed in 31% of samples. Interestingly, 63.5% of all mutations had been previously associated with cancer. Most (62.5%) of the missense BRAF exon 15 mutations found in the ALM samples examined here were deemed "detrimental" for protein function according to at least 2 functional prediction programs, and 3 mutations (37.5%) were predicted to be "neutral," with no effect on protein function. BRAF exon 15 mutations were detected frequently in ALM and displayed heterogeneity, a finding to be further investigated.
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Affiliation(s)
- Mariana Fernandes
- Department of Pathology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Denise Barcelos
- Department of Pathology, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | | | | | - Leonardo Cardili
- Department of Pathology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Lais de Sousa Morães
- Department of Morphology and Genetics, Federal University of São Paulo, São Paulo, Brazil
| | - Janete Cerutti Ap
- Department of Morphology and Genetics, Federal University of São Paulo, São Paulo, Brazil
| | - Gilles Landman Ap
- Department of Pathology, Universidade Federal de São Paulo, São Paulo, Brazil
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Grzywa TM, Paskal W, Włodarski PK. Intratumor and Intertumor Heterogeneity in Melanoma. Transl Oncol 2017; 10:956-975. [PMID: 29078205 PMCID: PMC5671412 DOI: 10.1016/j.tranon.2017.09.007] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/14/2017] [Accepted: 09/17/2017] [Indexed: 12/25/2022] Open
Abstract
Melanoma is a cancer that exhibits one of the most aggressive and heterogeneous features. The incidence rate escalates. A high number of clones harboring various mutations contribute to an exceptional level of intratumor heterogeneity of melanoma. It also refers to metastases which may originate from different subclones of primary lesion. Such component of the neoplasm biology is termed intertumor and intratumor heterogeneity. These levels of tumor heterogeneity hinder accurate diagnosis and effective treatment. The increasing number of research on the topic reflects the need for understanding limitation or failure of contemporary therapies. Majority of analyses concentrate on mutations in cancer-related genes. Novel high-throughput techniques reveal even higher degree of variations within a lesion. Consolidation of theories and researches indicates new routes for treatment options such as targets for immunotherapy. The demand for personalized approach in melanoma treatment requires extensive knowledge on intratumor and intertumor heterogeneity on the level of genome, transcriptome/proteome, and epigenome. Thus, achievements in exploration of melanoma variety are described in details. Particularly, the issue of tumor heterogeneity or homogeneity given BRAF mutations is discussed.
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Affiliation(s)
- Tomasz M Grzywa
- The Department of Histology and Embryology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-091 Warsaw, Poland
| | - Wiktor Paskal
- The Department of Histology and Embryology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-091 Warsaw, Poland
| | - Paweł K Włodarski
- The Department of Histology and Embryology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, 02-091 Warsaw, Poland.
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