Immunohistochemical evaluation of p16INK4A, E-cadherin, and cyclin D1 expression in melanoma and Spitz tumors

Combined utility of p16 and BRAF V600E in the evaluation of spitzoid tumors: Superiority to PRAME and correlation with FISH

BACKGROUND

Spitzoid melanocytic neoplasms are diagnostically challenging; criteria for malignancy continue to evolve. The ability to predict chromosomal abnormalities with immunohistochemistry (IHC) could help select cases requiring chromosomal evaluation.

METHODS

Fluorescence in situ hybridization (FISH)-tested spitzoid neoplasms at our institution (2013-2021) were reviewed. p16, BRAF V600E, and preferentially expressed antigen in melanoma (PRAME) IHC results were correlated with FISH.

RESULTS

A total of 174 cases (1.9F:1M, median age 28 years; range, 5 months-74 years) were included; final diagnoses: Spitz nevus (11%), atypical Spitz tumor (47%), spitzoid dysplastic nevus (9%), and spitzoid melanoma (32%). Sixty (34%) were FISH positive, most commonly with absolute 6p25 gain (RREB1 > 2). Dermal mitotic count was the only clinicopathologic predictor of FISH. Among IHC-stained cases, p16 was lost in 55 of 134 cases (41%); loss correlated with FISH positive (p < 0.001, Fisher exact test). BRAF V600E (14/88, 16%) and PRAME (15/56, 27%) expression did not correlate with FISH alone (p = 0.242 and p = 0.359, respectively, Fisher exact test). When examined together, however, p16-retained/BRAF V600E-negative lesions had low FISH-positive rates (5/37, 14%; 4/37, 11% not counting isolated MYB loss); all other marker combinations had high rates (56%-75% of cases; p < 0.001).

CONCLUSIONS

p16/BRAF V600E IHC predicts FISH results. "Low-risk" lesions (p16⁺ /BRAF V600E^- ) uncommonly have meaningful FISH abnormalities (11%). PRAME may have limited utility in this setting.

Circ_0084043-miR-134-5p axis regulates PCDH9 to suppress melanoma

The low survival rates, poor responses, and drug resistance of patients with melanoma make it urgent to find new therapeutic targets. This study investigated whether the circ_0084043-miR-134-5p axis regulates the antitumor effect of protocadherin 9 (PCDH9) in melanoma. Ectopic expression or knock down (KD) of PCDH9 with a lentivirus vector, we explored its effects on the proliferation, invasion, and apoptosis of melanoma and verified its regulatory effect on ras-related C3 botulinum toxin substrate 1 (RAC1), proline-rich tyrosine kinase 2 (Pyk2), Cyclin D1, matrix metalloproteinase 2 (MMP2), and MMP9. We further observed the effect of KD circ_0084043 on the malignant behavior of melanoma and studied whether circ_0084043 sponged miR-134-5p and regulated PCDH9. We found that circ_0084043 was overexpressed in melanoma and associated with the malignant phenotype. PCDH9 was poorly expressed in human melanoma tissues, and overexpression of PCDH9 inhibited melanoma progression. Quantitative real-time PCR and Western blotting results showed that overexpression of PCDH9 could downregulate RAC1, MMP2, and MMP9 and upregulate Pyk2 and Cyclin D1. Circ_0084043 KD inhibited invasion and promoted apoptosis in melanoma cells. Circ_0084043 could sponge miR-134-5p and thus indirectly regulate PCDH9. Furthermore, we discovered that inhibiting circ_0084043 had an anti–PD-Ll effect. In vivo, PCDH9 overexpression inhibited melanoma tumor growth, but PCDH9 KD promoted it. In conclusion, PCDH9, which is regulated by the circ 0084043-miR-134-5p axis, can suppress malignant biological behavior in melanoma and influence the expression levels of Pyk2, RAC1, Cyclin D1, MMP2, and MMP9.

Absence of Differential Cyclin D1 Immunohistochemical Protein Expression in Nevi and Melanoma Evaluated by Digital Image Analysis

BACKGROUND

Distinction of superficial spreading melanoma (SSM) from compound nevi (CN) sometimes poses difficult diagnostic challenges. Herein, we studied cyclin D1 protein expression by immunohistochemistry in SSM and CN and evaluated the results by digital image analysis.

DESIGN

A total of 13 CN and 12 SSM cases were retrospectively reviewed and cyclin D1 immunohistochemistry was performed. Immunohistochemical stained slides were evaluated by digital imaging analysis that included quantification and staining intensity of the cyclin D1 expressing dermal cells.

RESULTS

Cyclin D1 expression was observed in all CN and SSM. CN-positive staining was present in 30% to 93% of the dermal nevocytes, more positive in the upper (mean 85%), than lower half (mean 57%). SSM-positive staining was present in 44% to 96% of the dermal lesion, more positive in the upper (mean 88%) than lower half (mean 49%). When analyzed based on 3+ strong staining intensity, similar regional differences in cyclin D1 expression were observed.

CONCLUSIONS

Digital image analysis of Cyclin D1 expression showed no differences between CN and SSM. Quantity and regional distribution of cyclin D1 positivity were found to be similar in both lesions. Our findings argue against the routine use of cyclin D1 immunohistochemistry as a diagnostic tool for differentiating CN from SSM.

Cutaneous Melanomas: A Single Center Experience on the Usage of Immunohistochemistry Applied for the Diagnosis

Cutaneous melanoma (cM) is the deadliest of all primary skin cancers. Its prognosis is strongly influenced by the stage at diagnosis, with early stages having a good prognosis and being potentially treatable with surgery alone; advanced stages display a much worse prognosis, with a high rate of recurrence and metastasis. For this reason, the accurate and early diagnosis of cM is crucial-misdiagnosis may have extremely dangerous consequences for the patient and drastically reduce their chances of survival. Although the histological exam remains the "gold standard" for the diagnosis of cM, a continuously increasing number of immunohistochemical markers that could help in diagnosis, prognostic characterization, and appropriate therapeutical choices are identified every day, with some of them becoming part of routine practice. This review aims to discuss and summarize all the data related to the immunohistochemical analyses that are potentially useful for the diagnosis of cM, thus rendering it easier to appropriately applicate to routine practice. We will discuss these topics, as well as the role of these molecules in the biology of cM and potential impact on diagnosis and treatment, integrating the literature data with the experience of our surgical pathology department.

An update on the implications of cyclin D1 in melanomas

Cyclin D1 is a protein encoded by the CCND1 gene, located on 11q13 chromosome, which is a key component of the physiological regulation of the cell cycle. CCND1/cyclin D1 is upregulated in several types of human tumors including melanoma and is currently classified as an oncogene that promotes uncontrolled cell proliferation. Despite the demonstrated importance of CCND1/cyclin D1 as a central oncogene in several types of human tumors, its knowledge in melanoma is still limited. This review examines data published on upregulation of the CCND1 gene and cyclin D1 protein in the melanoma setting, focusing on the pathways and molecular mechanisms involved in the activation of the gene and on the clinical and therapeutic implications.

Immunohistochemical Expression of p16 in Melanocytic Lesions: An Updated Review and Meta-analysis

CONTEXT

- Making an accurate diagnosis for melanocytic lesions has always been challenging for pathologists, especially when dealing with difficult-to-diagnose cases. Misdiagnosis of melanoma and melanocytic lesions in general has tremendous medical-legal implications, often leading to unnecessary and excessive use of adjunctive tests. Although molecular testing is of much interest and there is great support for its development, currently, for most melanocytic lesions, immunohistochemical studies remain the most practical method for assistance in the routine diagnosis of melanocytic lesions for the average pathologist.

OBJECTIVES

- To review the practical use of p16 immunohistochemistry for evaluating melanocytic lesions, particularly for differentiating benign from malignant tumors, and to perform a meta-analysis of primary studies evaluating p16 immunohistochemistry in melanocytic lesions.

DATA SOURCES

- A PubMed database search for literature reporting melanocytic lesions and p16 immunohistochemistry was performed. Essential information from each study (number of samples, antibody used, collection dates, overall p16 immunohistochemistry results, and general method of interpretation) was tabulated and analyzed. Examples of representative cases showing p16 immunostaining pattern are also illustrated.

CONCLUSIONS

- Incorporation of p16 immunohistochemistry for the diagnosis of melanocytic lesions is of limited use, especially for the purpose of differentiating benign from malignant lesions. Evaluation of multiple studies reveals a wide range of results. However, there appears to be some value for the use of p16 in distinguishing nodal nevi from metastatic melanoma within nodes. The method of interpretation (nuclear versus cytoplasmic staining) also appears to give differing results, as studies considering only nuclear staining appeared to show more consistent results from study to study.

Expression of p15 in a spectrum of spitzoid melanocytic neoplasms

BACKGROUND

Accurate classification of spitzoid melanocytic lesions is difficult due to overlapping clinical and histopathologic features between Spitz nevi, atypical Spitz tumors (ASTs), and spitzoid melanomas. Expression of p16 (CDKN2A) has been used as a marker of spitzoid lesions. However, its expression may be variable. p15 is a tumor suppressor encoded by CDKN2B, loss of which has been recently shown to promote transition from nevus to melanoma. We sought to determine whether p15 is a useful immunohistochemical marker to distinguish Spitz nevi from spitzoid melanomas and to compare p15 and p16 staining in this population.

METHODS

Immunohistochemistry for p15 and p16 was performed on Spitz nevi (n = 19), ASTs (n = 41), and spitzoid melanomas (n = 17). Immunoexpression was categorized by a four-tiered system: 0 (negative), 1+ (weak), 2+ (moderate), 3+ (strong).

RESULTS

3+/strong p15 staining was observed in 68.4% of Spitz nevi, 34.2% of ASTs, and 17.7% of spitzoid melanomas. By contrast, we observed 3+ p16 staining in roughly equivalent percentages of Spitz nevi (57.9%), ASTs (56.1%), and spitzoid melanomas (58.8%).

CONCLUSION

These data illustrate that p15 may be more useful than p16 as a biomarker to help distinguish benign from malignant spitzoid lesions.

Immunohistochemical Detection of p16 in Clinical Samples

P16 immunohistochemical expression, a surrogate marker of the retinoblastoma pathway, has become a major adjunct in the routine practice mostly of cervical and head/neck pathology, but with other indications too. In this chapter, a detailed immunohistochemical technique for the detection of p16 is described, followed by indications and interpretation of its expression in uterine, ovarian, vulvar, penile, head-and-neck, melanocytic, and other pathologies.

Treatment of melanoma with selected inhibitors of signaling kinases effectively reduces proliferation and induces expression of cell cycle inhibitors

Cancer treatment often tends to involve direct targeting enzymes essential for the growth and proliferation of cancer cells. The aim of this study was the recognition of the possible role of selected protein kinases: PI3K, ERK1/2, and mTOR in cell proliferation and cell cycle in malignant melanoma. We investigated the role of protein kinase inhibitors: U0126 (ERK1/2), LY294002 (PI3K), rapamycin (mTOR), everolimus (mTOR), GDC-0879 (B-RAF), and CHIR-99021 (GSK3beta) in cell proliferation and expression of crucial regulatory cell cycle proteins in human melanoma cells: WM793 (VGP) and Lu1205 (metastatic). They were used either individually or in various combinations. The study on the effect of signaling kinases inhibitors on proliferation—BrdU ELISA test after 48–72 h. Their effect on the expression of cell cycle regulatory proteins: cyclin D1 and D3, cyclin-dependent kinase CDK4 and CDK6, and cell cycle inhibitors: p16, p21, and p27, was studied at the protein level (western blot). Treatment of melanoma cells with protein kinase inhibitors led to significantly decreased cell proliferation except the use of a GSK-3β kinase inhibitors—CHIR-99021. The significant decrease in the expression of selected cyclins and cyclin-dependent kinases (CDKs) with parallel increase in the expression of some of cyclin-dependent kinases inhibitors and in consequence meaningful reduction in melanoma cell proliferation by the combinations of inhibitors of signaling kinases clearly showed the crucial role of AKT, ERK 1/2, and mTOR signal transduction in melanoma progression. The results unanimously indicate those pathways as an important target for treatment of melanoma.

A small multimarker panel using simple immunohistochemistry methods is an adjunct to stage for cutaneous melanoma prognosis

Melanoma is an aggressive cancer. Outcomes can vary significantly for lesions within the same pathological stage - a problem of increasing relevance with the promise of adjuvant treatments on the basis of immune checkpoint modulators and targeted therapies. The use of a panel of prognostic molecular biomarkers as an adjunct to stage represents a possible solution. Immunohistochemistry-based biomarkers offer greater potential for translation into clinical practice than biomarkers utilizing more complex methods. Many immunohistochemistry-based biomarkers have been identified through discovery studies, but rigorous validation of these is scarce. We take the first steps towards validating a combination of three such biomarkers in a prognostic panel - 5hmC, ki-67 and p16. Immunohistochemistry was performed on a cohort of 50 melanomas to determine the expression of 5hmC, ki-67 and p16. 5hmC and p16 showed statistically significant differences in metastasis-free survival between low-score and high-score groups, whereas the use of all three biomarkers together with stage could predict the 5-year metastasis risk more accurately than stage alone. Our results suggest that the use of multimarker panels to improve the accuracy of prognostic predictions is feasible and worthy of further study. We have shown that a small immunohistochemistry-based panel utilizing simple, inexpensive, reproducible methods can be an effective adjunct to stage in prognostic prediction. A follow-up study consisting of a large cohort of melanomas is now indicated to continue the development of the prognostic panel.

Metastatic pathways in patients with cutaneous melanoma

Metastasis represents the end product of an elaborate biological process, which is determined by a complex interplay between metastatic tumour cells, host factors and homoeostatic mechanisms. Cutaneous melanoma can metastasize haematogenously or lymphogenously. The three predominant models that endeavour to explain the patterns of melanoma progression are the stepwise spread model, the simultaneous spread model and the model of differential spread. The time course to the development of metastases differs between the different metastatic routes. There are several clinical and histopathological risk factors for the different metastatic pathways. In particular, patient sex and the anatomical location of the primary tumour influence patterns of disease progression. There is limited existing evidence regarding the relationship between tumour mutation status, other diagnostic and prognostic biomarkers and the metastatic pathways of primary cutaneous melanoma. This knowledge gap needs to be addressed to better identify patients at high risk of disease recurrence and personalize surveillance strategies.

A diagnostic algorithm for atypical spitzoid tumors: guidelines for immunohistochemical and molecular assessment

Atypical spitzoid tumors are a morphologically diverse group of rare melanocytic lesions most frequently seen in children and young adults. As atypical spitzoid tumors bear striking resemblance to Spitz nevus and spitzoid melanomas clinically and histopathologically, it is crucial to determine its malignant potential and predict its clinical behavior. To date, many researchers have attempted to differentiate atypical spitzoid tumors from unequivocal melanomas based on morphological, immonohistochemical, and molecular diagnostic differences. A diagnostic algorithm is proposed here to assess the malignant potential of atypical spitzoid tumors by using a combination of immunohistochemical and cytogenetic/molecular tests. Together with classical morphological evaluation, this algorithm includes a set of immunohistochemistry assays (p16(Ink4a), a dual-color Ki67/MART-1, and HMB45), fluorescence in situ hybridization (FISH) with five probes (6p25, 8q24, 11q13, CEN9, and 9p21), and an array-based comparative genomic hybridization. This review discusses details of the algorithm, the rationale of each test used in the algorithm, and utility of this algorithm in routine dermatopathology practice. This algorithmic approach will provide a comprehensive diagnostic tool that complements conventional histological criteria and will significantly contribute to improve the diagnosis and prediction of the clinical behavior of atypical spitzoid tumors.

Immunohistochemical evaluation of p16 expression in cutaneous histiocytic, fibrohistiocytic and undifferentiated lesions

BACKGROUND

Expression of p16 is frequently evaluated in melanocytic lesions. Expression of p16 in cutaneous histiocytic, fibrohistiocytic and undifferentiated lesions has not been well characterized.

METHODS

We evaluated p16 expression in a cohort of histiocytic (reticulohistiocytoma, Langerhans cell histiocytosis, xanthogranuloma, Rosai Dorfman disease and xanthoma), fibrohistiocytic (dermatofibroma, epithelioid fibrous histiocytoma and dermatofibrosarcoma protuberans) and undifferentiated (atypical fibroxanthoma and pleomorphic undifferentiated sarcoma) lesions. A group of melanocytic lesions (Spitz nevus, ordinary nevus, spitzoid melanoma and non-spitzoid melanoma) were also evaluated as reference. Each case was scored by the proportion of p16-positive cells and by staining intensity.

RESULTS

Immunoreactivity for p16 was found in almost all histiocytic (28/30, 93%) and fibrohistiocytic (22/24, 92%) lesions. About half of the undifferentiated lesions also exhibited p16 staining (9/17, 53%). Most of the melanocytic cases examined in this study expressed p16. A wide range of staining intensity and proportion of p16-positive cells was observed in most groups.

CONCLUSION

Expression of p16 is common, albeit variable in proportion and intensity, amongst a wide variety of cutaneous histiocytic, fibrohistiocytic and undifferentiated lesions. Further studies are required to determine if p16 expression is useful in distinguishing benign from malignant neoplasms of these types.

Clinical Follow-up of Atypical Spitzoid Tumors Analyzed by Fluorescence In Situ Hybridization

Many neoplasms with spitzoid features remain enigmatic, especially those with intermediate grade features or "atypical spitzoid tumors" (ASTs). Fluorescence in situ hybridization (FISH) has emerged as a complementary technique to conventional microscopy, with certain chromosomal patterns conveying diagnostic information. In this study, we examined 36 ASTs analyzed by FISH for specific abnormalities in chromosomes 6, 9, and 11. Aberrations were detected in 11 cases, 7 of which met FISH criteria for spitzoid melanoma. These had homozygous deletion of 9p21, partial deletion of 11q13, gain of 6p25, and gain of 11q13. All 3 patients with positive sentinel lymph nodes, including one with progression beyond the sentinel lymph node, had homozygous deletion of chromosome 9p21, but there were no deaths in an average of 28 months of follow-up of these cases. Other aberrations in the chromosomal pattern of ASTs were heterozygous deletion of 9p21, partial deletion of 6p23, and tetraploidy. We found that ASTs, including those eventually diagnosed as spitzoid melanoma, had a more indolent course in our cohort than conventional malignant melanoma. Moreover, the addition of FISH results led to a more definitive diagnosis in 7 cases, 4 of which had abnormalities on FISH consistent with spitzoid melanoma.

Atypical Spitz Tumors: A Diagnostic Challenge

Spitzoid melanocytic lesions encompass a spectrum from benign Spitz nevi to malignant spitzoid melanomas. Spitzoid melanocytic neoplasms have significant morphologic and molecular differences from conventional melanocytic lesions, and prediction of biologic behavior and metastatic risk may be difficult. Most challenging is the atypical Spitz tumor, a borderline spitzoid melanocytic lesion of uncertain malignant potential that has overlapping histologic features with conventional Spitz nevus and spitzoid melanoma. Atypical Spitz tumors involve the sentinel lymph nodes at a greater frequency than conventional melanoma and frequently harbor chromosomal copy number changes, yet most cases follow an indolent course. Herein we review the clinical, microscopic, and molecular features of atypical Spitz tumors, including recent molecular advances, including the potential prognostic significance of chromosomal abnormalities, such as homozygous CDKN2A loss.

Immunohistochemistry in dermatopathology

CONTEXT

Immunohistochemistry is not a diagnostic test but a highly valuable tool that requires interpretation within a context.

OBJECTIVE

To review the current status and limitations of immunohistochemistry in dermatopathology.

DATA SOURCES

English-language literature published between 1980 and 2014.

CONCLUSIONS

Although immunohistochemistry is rarely completely specific or sensitive, it is an important adjunctive technique in dermatopathology and can be helpful in a series of diagnostic dilemmas.

α-Methylacyl-coenzyme A racemase (AMACR, p504s) is a marker to distinguish malignant melanomas from dysplastic nevi and melanocytic nevi

Routinely processed skin biopsies are still the mainstay for the diagnosis of melanocytic skin neoplasms (MSNs) and are considered the "gold standard" for individual patient management and clinical trials. The diagnostic challenge of melanocytic lesions of the skin prompts histopathologists to consider new diagnostic tools; among these, immunohistochemistry. We aimed to find putative new immunohistochemical markers, which can supplement the histological criteria used to detect dysplasia. In this immunohistochemical study, we chose a panel of promising biomarkers which could potentially differentiate between different MSN entities. These included α-methylacyl-coenzyme A racemase (AMACR; p504s), which is involved in the degradation of branched chained fatty acid derivates. We analysed a cohort of benign nevi and malignant melanomas. The design of the study included 78 melanocytic skin neoplasms (26 malignant melanomas and 52 benign nevi) in a tissue microarray. Immunohistochemistry of cyclin-dependent kinase inhibitor 2A (p16Ink4a), methylacyl-coenzyme A racemase (AMACR), cyclin D1, and E-cadherin was performed and assessed. We have observed that the p16Ink4a, AMACR, cyclin D1, and E-cadherin showed no exclusive staining for nevi or melanomas. However, a significant overexpression of AMACR was found in malignant melanomas compared to benign nevi. AMACR overexpression was also associated with an increased p16Ink4a staining. Our results suggest AMACR as an immunohistochemical marker for distinguishing malignant melanomas and dysplastic nevi from conventional melanocytic nevi.

p16 Expression Is Lost in Severely Atypical Cellular Blue Nevi and Melanoma Compared to Conventional, Mildly, and Moderately Atypical Cellular Blue Nevi

Background. Significant decreases in p16 expression have been shown to occur in melanoma compared to Spitz tumors, and loss of p16 staining has been found to correlate with melanoma tumor progression. However, comparison of p16 between atypical cellular blue nevi (CBN) and melanoma has not been reported previously. Methods. p16 immunohistochemical staining was evaluated in 14 atypical CBN, 8 conventional and atypical melanocytic nevi, and 16 melanomas, including 4 malignant CBN. p16 staining intensity was graded on a scale of 0–3 and the percentage of melanocytes stained with p16 was determined. Results. p16 staining was significantly higher in all CBN as a group when compared to melanomas (P = 0.001) and malignant CBN (P = 0.00008). Higher p16 expression was also seen in mildly (P = 0.0002) and moderately atypical (P = 0.02), but not severely atypical, CBN compared to melanomas. Conclusions. p16 immunohistochemical expression is higher in mildly and moderately atypical CBN compared to severely atypical CBN and melanomas. In conjunction with additional markers and histology, p16 staining may be useful in confirming the benign nature of these tumors, but is not useful in distinguishing severely atypical CBN from malignant cases, consistent with the overlapping histologic features between these tumors.

9p21 gene locus in Spitz nevi of older individuals: absence of cytogenetic and immunohistochemical findings associated with malignancy

The diagnosis of Spitz nevus in an elderly individual is often met with skepticism because the lesion can be difficult to distinguish from melanoma and because the probability of a malignant melanoma is higher in older patients. Recently, increased sensitivity for detection of malignant spitzoid neoplasms using 9p21 fluorescence in situ hybridization (FISH) has been described. In this study, we address the question of whether histopathologically typical Spitz nevi occurring in patients 50 years and older show any abnormalities regarding the 9p21 CDKN2A tumor suppressor gene locus. p16 immunohistochemistry (IHC), as well as dual-color FISH for assessment of diploid or hypodiploid status at 9p21, was performed in 25 classic Spitz nevi from patients 50 years and older and was compared with findings in a younger control population. All cases of typical Spitz nevi occurring in older patients retained p16 expression by immunohistochemistry and showed normal, diploid 9p21 FISH signals. Heterozygous loss of 9p21 by FISH was noted in a control case of a 9-year-old girl and is of unknown significance. These findings indicate that p16 expression by immunohistochemistry in classic Spitz nevi correlates well with absence of malignancy-associated cytogenetic abnormalities at 9p21 by FISH independent of the patient's age. Assessment of p16 expression by standard immunohistochemistry may therefore be reassuring in routine clinical practice when the patient is of advanced age, and can be helpful as a screening tool to select IHC-negative cases for extended FISH analysis targeting the 9p21 gene locus.

Intratumoral heterogeneity of chromosome 9 loss and CDKN2A (p16) protein expression in a morphologically challenging spitzoid melanoma

In young adults and children, spitzoid melanoma carries striking resemblance to spitz nevus clinically and histopathologically. Many have attempted to differentiate between these 2 entities by searching for immunohistochemical and molecular diagnostic differences. Here, the authors report a spitzoid melanoma in a young adult, which was morphologically similar to a spitzoid nevus and carried a loss of chromosome 9 detected by an array-based comparative genomic hybridization. However, the expression of cyclin-dependent kinase inhibitor 2A (p16) protein, encoded on chromosome 9p21, detected by the immunohistochemical study was heterogeneous among tumor cells. This case demonstrates the presence of clonal heterogeneity of losses of chromosome 9 and p16 protein expression within a single spitzoid melanoma, challenging a robust application of p16 expression detected only by immunohistochemical staining in determining the diagnosis of spitzoid melanoma.

The Impact of Molecular Morphology Techniques on the Expert Diagnosis in Melanocytic Skin Neoplasms

Thirteen melanocytic skin neoplasms with a consultation diagnosis by A. Bernard Ackerman were submitted to immunohistochemistry for HMB-45, Ki67, cyclin D1, e-cadherin, and p16; 9/13 cases underwent fluorescence in situ hybridization (FISH) test targeting 6p25 (RREB1), 6q23 (MYB), centromere 6 (Cep6), and 11q13 (CCND1), as well as the centromere 7 (Cep7). A “consensus diagnosis” among 3 experts was also advocated both before and after morphomolecular information. Three neoplasms with a consultation diagnosis of Spitz nevus showed at least 3 abnormal immunohistochemical patterns; 2 of these cases were also FISH-positive for CCND1 gain, but none of them had a final consensus diagnosis of melanoma. Two neoplasms with a consultation diagnosis of congenital nevus received a consensus diagnosis of melanoma. Molecular morphology techniques can highlight the atypical features of melanocytic neoplasms and support existence of a morphobiologic “spectrum”: This should be mirrored in the final report by abandoning the dichotomic (benign vs malignant) diagnostic approach.

Update in molecular diagnostics in melanocytic neoplasms

Future classification systems for melanocytic neoplasms will likely include the integration of molecular aberrations. A number of studies have shown that many gene mutations and chromosomal copy number aberrations may correlate with characteristic clinical and morphologic features for melanocytic neoplasms. This review discusses newly described familial germline mutations such as the BRCA1-associated protein-1 familial melanoma syndrome, recently described somatic mutations, and chromosomal copy number aberrations recently described in melanoma. Further, we discuss how these specific molecular aberrations correlate with specific clinical and morphologic features in melanocytic neoplasm and their implications for prognosis and molecular diagnostics. In addition, we discuss state of the art advancements in molecular diagnostics for melanocytic neoplasms and newly developed fluorescence in situ hybridization assays including the utility of fluorescence in situ hybridization for 9p21 in spitzoid melanocytic neoplasms. Lastly, we discuss a phenomenon known as paradoxical activation of wild-type BRAF seen in patients treated with vemurafenib and some potential clinical presentations of this process.

Loss of microRNA-200a and c, and microRNA-203 expression at the invasive front of primary cutaneous melanoma is associated with increased thickness and disease progression

Loss of E-cadherin expression in melanoma correlates with increased tumor thickness and reduced disease-free survival. The molecular mechanisms underpinning its differential expression in melanoma tissue remain elusive. MicroRNAs (miRNAs) have been implicated in tumor progression and regulation of E-cadherin expression. Here, we demonstrate a significant correlation between tumor thickness and loss of expression of miR-200a, miR-200c, and miR-203 in a series of 23 frozen primary melanomas, where it was confirmed in two subsequent validation series (series 1: six nevi, 15 primary melanomas, and 16 metastases; series 2: 11 matched pairs of primary melanomas and metastases). Decreased levels of miR-200a, miR-200c, and miR-203 correlated with increasing thickness in the combined validation series (P = 0.024, 0.033, and 0.031, respectively). In addition, progressive loss of miR-200a expression with disease progression was observed in series 1 (P < 0.001) and in series 2 (P = 0.029). MiR-200 in situ hybridization and E-cadherin immunohistochemistry demonstrated reduced expression of both at the deep invasive margin of the tumor. Furthermore, a functional validation study using an anti-miR200 strategy demonstrated that loss of miR-200 expression in melanoma cell lines reduced E-cadherin expression. Collectively, our data point towards an important role for miR-200 and miR203 expression in regulating E-cadherin during melanoma progression.

Update on immunohistochemistry in melanocytic lesions

This article is an up-to-date overview of the potential uses and limitations of immunohistochemistry (IHC) in melanocytic lesions. The information is intended to assist dermatopathologists and dermatologists who read slides to appropriately use IHC in this setting. In addition, dermatologists who do not review microscopic slides will better understand the rationale of the pathologist when reading and interpreting the pathology report.

Spitz nevi and other Spitzoid lesions part I. Background and diagnoses

Spitz nevi are melanocytic proliferations that are characterized by spindled and/or epithelioid nevomelanocytes. First interpreted as juvenile melanoma, these lesions were later characterized as benign and were observed to affect all age groups. Today, contrasting opinions persist regarding the fundamental benignancy versus malignancy within the spectrum of Spitz tumors. Beyond clinical outcome, this controversy has also been fueled by complex and sometimes convoluted classification schemes based on pathologic characteristics. More recently, immunophenotypic and molecular analyses have begun to clarify the etiologic nature of these tumors. Recent evidence suggests that histopathologic features that suggest more aggressiveness in Spitz tumors relate to mitoses and inflammation.

Pigmented spindle cell nevus: clues for differentiating it from spindle cell malignant melanoma. A comprehensive survey including clinicopathologic, immunohistochemical, and FISH studies

Pigmented spindle cell nevus (PSCN), also known as Reed nevus, is a distinctive melanocytic tumor that can show worrisome clinical and histologic features mimicking a malignant melanoma. From a series of 46 pigmented spindle cell melanocytic lesions, including 22 PSCN and 24 spindle cell malignant melanomas (SCMMs), we collected clinical and histopathologic characteristics and evaluated cell cycle and apoptosis regulators by immunohistochemistry. Moreover, fluorescence in situ hybridization (FISH) using probes targeting 6p25 (RREB1), 11q13 (CCND1), 6q23 (MYB), and centromere 6 was performed. PSCN presented in younger people, frequently in women, and were small lesions under 7 mm in diameter affecting the lower limbs, whereas SCMMs arose more frequently in the trunk, upper limbs, and head and neck region. Histologically, symmetry, good lateral demarcation, and uniformity of cellular nests were significantly differential features of PSCN, whereas pagetoid and adnexal spread were frequently seen in both tumors. Immunohistochemical markers that significantly differed from melanomas were Ki-67, cyclin D1, and survivin. FISH was positive in 1 of 15 PSCN and was negative in 4 of 15 SCMMs. These results correlated to a sensitivity of 73% and a specificity of 93%. In conclusion, in the evaluation of pigmented spindle cell melanocytic tumors, the integration of clinical and histologic assessment is essential. However, ancillary techniques such as proliferation antigen Ki-67, cyclin D1, survivin, and FISH can be useful as adjunctive tools.

Melanoma update: diagnostic and prognostic factors that can effectively shape and personalize management

Routine light microscopy remains a powerful tool to diagnose, stage and prognose melanoma. Although it is very economical and efficient, it requires a significant level of expertise and, in difficult cases the final diagnosis is affected by subjective interpretation. Fortunately, new insights into the genomic aberrations characteristic of melanoma, coupled with ancillary studies, are further refining evaluation and management allowing for more confident diagnosis, more accurate staging and the selection of targeted therapy. In this article, we review the standard of care and new updates including four probe FISH, the 2009 American Joint Commission on Cancer staging of melanoma and mutant testing of melanoma, which will be crucial for targeted therapy of metastatic melanoma.

Clinical significance of serum levels of soluble E-cadherin in patients with gastric carcinoma

AIM: To measure serum levels of soluble E-cadherin (sE-cadherin) in patients with gastric cancer and to evaluate the relationship of serum levels of sE-cadherin with tumor clinicopathological features and patient survival.

METHODS: Peripheral blood samples were collected from 127 gastric cancer patients and 31 healthy controls from March 2003 to September 2004. Serum levels of sE-cadherin were measured using double-antibody sandwich enzyme-linked immunosorbent assay. The clinical pathological data and survive data for all patients were recorded.

RESULTS: Serum levels of sE-cadherin were significantly higher in patients with gastric cancer than in healthy controls (43.83 μg/L ± 15.77 μg/L vs 17.17 μg/L ± 5.38 μg/L, P = 0.000, t = 8.34). Serum levels of sE-cadherin were closely associated with tumor differentiation, depth of invasion and lymph node metastasis (all P < 0.05). Patients with lower levels of serum sE-cadherin had significant survival advantage over those with higher levels of serum sE-cadherin (P < 0.001), and such survival advantage was independent of depth of invasion, lymph node metastasis and tumor differentiation.

CONCLUSION: sE-cadherin may serve as a potential biological marker for the diagnosis and prognosis of gastric cancer.

Expression of connexin 43 and E-cadherin in choroidal melanoma

AIM

To investigate the expression of connexin 43 and epithelial cadherin (E-cadherin) in choroidal melanoma, to explore the clinical and pathological implications of expression of these proteins, and to determine their relations with malignant features.

METHODS

The expression of connexin 43 and E-cadherin in choroidal melanoma were detected by immunohistochemistry and correlated with clinicopathological features.

RESULTS

Positive rates of connexin 43 in choroidal melanomas and benign pigmented nevus tissues were 75% and 40% respectively with significant differences between the two groups (χ(2)=5.607, P=0.009). Positive rates of E-cadherin in choroidal melanomas and benign pigmented nevus tissues were 40% and 75% respectively with significant differences between the two groups (χ(2)=5.214, P=0.010). Significant overexpression of connexin 43 and reduction of E-cadherin expression was associated with the invasion to the sclera, and there were respectively significant differences between without and with scleral invasion groups (χ(2)=2.880, P=0.040; χ(2)=2.778, P=0.046). Overexpression of connexin 43 were correlated with tumor cell types and the expression of connexin 43 and E-cadherin may be correlated with each other.

CONCLUSION

The increased expression of connexin 43 and the decreased expression of E-cadherin may be involved in the process of invasion of choroidal melanoma. The overepression of connexin 43 and reduction of E-cadherin may contribute to the development of choroidal melanoma.