BRAF V600 mutation detection in melanoma: a comparison of two laboratory testing methods

Low incidence of BRAF and NRAS mutations in a population with a high incidence of melanoma

Reported rates of BRAF mutation in Irish cutaneous melanoma cohorts are lower than the reported international data. We aimed to assess the mutational status of a cohort of primary cutaneous melanomas and to correlate it with clinical follow-up data.A total of 92 cases of primary cutaneous melanoma diagnosed at a single institution in 2012 were analyzed. Regions containing common mutations in the BRAF, NRAS, KIT, and KRAS genes were investigated by PCR amplification followed by Sanger sequencing. Demographic details, tumor characteristics, and 10-year outcome data were also obtained.Ten cases with BRAF V600E mutations (11.6%) and five (5.49%) NRAS mutations (4 at Q61R, 1 at Q61K) were detected. No statistically significant differences were noted between groups for age, gender, depth of invasion, nodal status, or recurrence status (p ≥ 0.05).These findings suggest that the Irish population has a markedly lower incidence of BRAF and NRAS mutations in melanoma than those reported in other cohorts.

BRAFV600E mutational status assessment in cutaneous melanocytic neoplasms in a group of the Egyptian population

BACKGROUND

Melanocytic neoplasms range from banal nevi to malignant melanomas. The genetic background has been extensively studied in the Caucasian population. BRAF mutations were reported among the early driver mutations in nevogenesis. Nevertheless, the pathogenesis in the Egyptian population has not been elucidated.

AIM AND METHODS

The present study was carried out to assess the sensitivity and specificity of immunohistochemistry (IHC) using the RM-08 clone in reference to allele-specific real-time PCR (CAST-PCR) for the detection of the BRAF V600E mutation in 50 formalin-fixed paraffin-embedded blocks of melanocytic neoplasms with prior bleaching using hydrogen peroxide in Tris-HCL and Bovine Serum Albumin respectively.

RESULTS

IHC staining was interpreted using staining reaction (positive versus negative) and staining pattern (negative and heterogeneous versus homogenous). Using the staining pattern, the specificity increased from 73.3 to 88.2%, the negative predictive value increased from 73.3 to 100%, the diagnostic accuracy increased from 71.4 to 90.48% and the overall accuracy increased from 69.9 to 77.3%. The sensitivity and positive predictive value remained unchanged. The K-agreement coefficient increased from 0.364 (fair agreement) to 0.741 (good agreement) and was statistically significant (p = 0.00). Next-generation sequencing was performed in 11 cases, 8 cases with IHC-positive and BRAF wild type in addition to 3 cases that failed PCR analysis and revealed no BRAF V600E. No statistically significant difference was found in the clinicopathological parameters between BRAF V600E and BRAF wild-type melanomas.

CONCLUSIONS

These findings suggest that IHC staining homogeneity may be more accurate in predicting BRAF V600E mutational status. However, IHC cannot replace molecular methods.

Actualities in the Morphology and Immunohistochemistry of Cutaneous and Ocular Melanoma: What Lies Ahead? A Single-Centre Study

Melanoma is the most aggressive melanocytic tumor whose incidence is continuously increasing worldwide.

METHODS

We highlight the morphological, immunohistochemistry, and particularities of various melanoma types based on the cases diagnosed in our department from 2017 to 2021.

RESULTS

We present 100 melanoma cases and one capsular nevus case. The most common type was nodular melanoma. The immunohistochemistry markers used were SRY-box transcription factor 10 (SOX10), S100 protein, human melanoma black 45 (HMB45), and melanoma antigen recognized by T cells 1 (Melan-A). Uveal melanoma and conjunctival melanoma represent particular tumors with independent prognostic factors. Uveal melanoma requires assessment of macrophages, microvascularisation, and mitoses. Sentinel lymph node metastases are essential targets that provide staging tools. Conjunctival melanoma and capsular nevi are diagnostic pitfalls.

CONCLUSION

Melanoma can appear in various forms, and sometimes the diagnosis might be unclear. Today, immunohistochemistry remains the most important tool in confirming the diagnosis and prognosis for this type of neoplasia.

Discrepancy between immunohistochemistry and sequencing for BRAF V600E in odontogenic tumours: Comparative analysis of two VE1 antibodies

BACKGROUND

Although immunohistochemistry (IHC) along with molecular tests has been investigated in ameloblastoma for BRAF V600E detection, VE1 IHC has not been studied in odontogenic carcinomas (OCs) and benign mixed epithelial and mesenchymal odontogenic tumours (BMOTs). Here, we performed BRAF V600E mutation analysis, examined the expression pattern of VE1 IHC, and comparatively evaluated the performance of two VE1 antibodies in ameloblastomas, OCs and BMOTs.

METHODS

BRAF V600E detection was performed using Sanger sequencing in a total of 47 odontogenic tumours: 28 ameloblastomas, 6 OCs and 13 BMOTs. VE1 IHC was conducted using two different antibodies (IHC-A and IHC-V), and their performance was analysed by calculating the sensitivity and specificity compared with sequencing.

RESULTS

BRAF V600E mutations were identified in 24/28 (85.7%) ameloblastomas, 2/5 (40.0%) ameloblastic carcinomas (ACs), 3/7 (42.9%) ameloblastic fibromas and 1/2 (50.0%) ameloblastic fibro-odontomas. In the presence of the mutation, VE1 showed diffuse cytoplasmic staining in ameloblastomas and ACs, whereas all BMOTs were negative for VE1. IHC-A and IHC-V yielded a sensitivity of 76.7% and 60.0%, respectively, although both antibodies showed 100% specificity.

CONCLUSION

OCs and BMOTs have BRAF V600E mutations in common at lower frequencies than ameloblastoma. Diffuse VE1 cytoplasmic staining in AC suggests the utility of MAPK-targeted therapy as selectively applied in ameloblastoma, and consistent VE1 false-negative expression in BMOTs requires further investigation. Considering the high specificity but low sensitivity of VE1 IHC, molecular tests should be performed to determine the presence of BRAF V600E mutations in odontogenic tumours.

Molecular and immunohistochemical analysis of BRAF gene in primary cutaneous melanoma: Discovery of novel mutations

BACKGROUND

Determination of BRAF status is mandatory for targeted therapy but it is not currently available in most developing countries.

AIM

We aimed to analyze BRAF mutations in a series of cutaneous melanoma of Tunisian patients and to compare BRAF V600E mutation detection by immunohistochemistry to DNA sequencing.

PATIENTS AND METHODS

Archival formalin fixed paraffin embedded tissues from 28 patients with primary cutaneous melanoma were evaluated for the BRAF mutations by Sanger sequencing and immunohistochemistry.

RESULTS

BRAF mutations were detected in 19/28 (68%) of analyzed tumors. The sensitivity and specificity of immunohistochemistry compared to DNA sequencing for identification of the BRAF V600E mutation were 100%. We found five novel mutations, one of them had deleterious effect.

CONCLUSION

The present study shows an intermediate frequency of mutations of the BRAF gene in cutaneous melanoma of Tunisian patients, and supports the use of immunohistochemistry as a screening test for the assessment of the BRAF V600E status in the management of melanoma in clinical practice.

BRAF Status in Papillary Microcarcinomas of the Thyroid Gland: a Brief Review

Papillary thyroid microcarcinoma (PTMC) is defined by the World Health Organization as papillary cancer measuring 10 mm or less in diameter. Generally, PTMC shows an indolent clinical behavior with a good prognosis, although a minority of PTMC is characterized by an aggressive course. However, efforts to identify this aggressive subset of PTMC after surgery remain inconclusive. Several oncogenic pathways have been identified in thyroid cancer and have been applied translationally to improve prognosis and clinical management. In particular, the BRAFV600E mutation was found more frequently in large, aggressive, recurrent and advanced tumors. We aimed at reviewing studies on BRAFV600E mutation as a prognostic factor in PTMC.

Detection of Gene Mutations in Liquid Biopsy of Melanoma Patients: Overview and Future Perspectives

OPINION STATEMENT

Liquid biopsies are still far from widely implanted in the clinical arena. Issues related to the added sensitivity of this test beyond conventional methods have not been fully resolved. Additionally, issues related to the specificity of these results especially as many cancers may share common mutation need further investigations. One way to resolve this may include the development and testing of large gene panels to add higher specificity. On the other hand, further studies are needed to support the idea that ctDNA or circulating tumor cells may constitute a better representation of the tumor subpopulation that is capable of metastasizing, which will strongly support its clinical value. Finally, survival studies showing a positive impact of this technology will also justify its widespread implementation in clinical practice.

Discrimination of the V600E Mutation in BRAF by Rolling Circle Amplification and Förster Resonance Energy Transfer

The quantification of very low concentrations of circulating tumor DNA (ctDNA) biomarkers from liquid biopsies has become an important requirement for clinical diagnostics and personalized medicine. In particular, the simultaneous detection of wild-type (WT) dsDNA and their cancer-related counterparts presenting single-point mutations with simple, sensitive, specific, and reproducible technologies is paramount for ctDNA assays in clinical practice. Here, we present the development and evaluation of an amplified dsDNA assay based on a combination of isothermal rolling circle amplification (RCA) and time-gated Förster resonance energy transfer (TG-FRET) between a Tb donor and two dye (Cy3.5 and Cy5.5) acceptors. The RCA-FRET assay is free of washing and separation steps and can quantify both WT and mutated (MT) (V600E) dsDNA in the BRAF gene from a single sample in the 75 fM to 4.5 pM (4.5 × 10⁵ to 2.7 × 10⁷ copies) concentration range. This assay includes all steps from denaturation of the dsDNA targets to the final duplexed quantification of WT and MT targets. High assay performance at different dsDNA sequence lengths and high target specificity even in the presence of a large excess of nonspecific cell-free DNA from human plasma samples demonstrated the applicability to clinical samples. The RCA-FRET single-point mutation sensor has the potential to become an important complementary technique for analyzing liquid biopsies in advanced cancer diagnostics.

Overview of established and emerging immunohistochemical biomarkers and their role in correlative studies in MRI

Clinical practice in radiology and pathology requires professional expertise and many years of training to visually evaluate and interpret abnormal phenotypic features in medical images and tissue sections to generate diagnoses that guide patient management and treatment. Recent advances in digital image analysis methods and machine learning have led to significant interest in extracting additional information from medical and digital whole-slide images in radiology and pathology, respectively. This has led to significant interest and research in radiomics and pathomics to correlate phenotypic features of disease with image analytics in order to identify image-based biomarkers. The expanding role of big data in radiology and pathology parallels the development and role of immunohistochemistry (IHC) in the daily practice of pathology. IHC methods were initially developed to provide additional information to help classify tumors and then transformed into an indispensable tool to guide treatment in many types of cancer. IHC markers are used in daily practice to identify specific types of cells and highlight their distributions in tissues in order to distinguish benign from neoplastic cells, determine tumor origin, subclassify neoplasms, and support and confirm diagnoses. In this regard, radiomics, pathomics, and IHC methods are very similar since they enable the extraction of image-based features to characterize various properties of diseases. Due to the dramatic advancements in recent radiomics research, we provide a brief overview of the role of established and emerging IHC biomarkers in various tumor types that have been correlated with radiologic biomarkers to improve diagnostic accuracy, predict prognosis, guide patient management, and select treatment strategies. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020;51:341-354.

An integrated multi-molecular sensor for simultaneous BRAFV600E protein and DNA single point mutation detection in circulating tumour cells

The analysis of circulating cancer biomarkers in the form of liquid biopsies confers several potential benefits as compared to traditional surgical tissue sampling. As a common key anomaly strongly implicated across several cancer types, the BRAFV600E mutation is one of the most valuable oncogenic biomarkers available in liquid biopsies. Crucially, BRAFV600E is also an actionable mutation which could be arrested by clinically beneficial drug inhibitors. Yet, as is true for most single base disease mutations, current BRAFV600E detection in either its DNA or protein molecular state is still liable to false positive/negative outcomes, thus impacting patient treatment benefit. Here we present an integrated multi-molecular sensor (IMMS) for an entire sample-to-answer workflow from melanoma cell capture to simultaneous quantification of both intracellular BRAFV600E DNA and protein levels on a single platform. The IMMS combines (i) specific capture and release of circulating melanoma cells; (ii) electric field-induced cell lysis; (iii) simultaneous quantification of BRAFV600E DNA and protein levels. We investigated the IMMS system's analytical performance in cell capture, release and lysis, and intracellular BRAFV600E detection by ligase-mediated DNA amplification and antibody-based protein hybridization. As a proof-of-concept, we successfully demonstrated circulating BRAFV600E detection at both DNA and protein molecular levels in simulated melanoma plasma samples. With its capabilities in integrated and miniaturized analysis, the IMMS could lead the emergence of a new generation of multi-molecular lab-on-chip biosensors for enabling more accurate and extensive analysis of powerful circulating biomarkers in patient liquid biopsies.

One Step Melanoma Surgery (OSMS) Without Using Ultrasonography for Preoperative Tumour Thickness Measurement? - "A Question that Sometimes Drives Me Hazy: Am I or Are the Others Crazy!"

BACKGROUND:

One step melanoma surgery is a new surgical approach by which specific groups of patients with cutaneous melanoma may be operated only by or within a single surgical session. Until now, the Bulgarian Society for Dermatologic Surgery (BULSDS) has presented models of clinical behaviour, in which preoperative measurement of tumour thickness in combination with echographic measurement of the locoregional lymph nodes could lead to the conduct of the so-called one-step melanoma surgery. Although this one step surgery currently does not fit in the recommended guidelines, it ensures compliance of the recommended boundaries of operational security while saving patients a repeated excision and relieves the healthcare institutions or the patients themselves financially.

CASE REPORT:

We at this moment present another case from the Bulgarian Society for Dermatologic Surgery (BULSDS) of one step melanoma surgery with a perfect end result, where the tumour thickness was not preoperatively determined by high-frequency echography. Preoperative assessment of tumour thickness was performed based on the clinical picture and dermatoscopy. The histologically established tumour thickness was identical to the preoperative assessment, i.e. <1 mm. Removal of the melanocytic lesion was performed with operational security field of 1cm in all directions, where, as a rule, no further removal of the draining lymph nodes is required.

CONCLUSION:

One step melanoma surgery has two significant advantages: 1) it saves a re-excision in certain groups of patients, which in turn is 2) significantly more favourable from a financial point of view. Its applicability in the appropriate groups of patients and the postoperative (although in a limited number of patients) results achieved indicate the need to optimise the current algorithms and direct them individually to each patient. Guidelines may not and should not be unified or set strict limits given the fact that they show a significant level of variability themselves regarding some key moments in the initial surgical treatment of melanoma. More than 10% of the primary melanoma cases refer to thin melanomas, and dermatoscopy and clinics are a sufficient method of optimising the planned surgical excision.