Proof of concept that melanoma nuclear count compares favourably with the benchmark histological prognostic feature, Breslow thickness.

AIMS: Breslow thickness (BT) is the most important histological prognostic feature for melanoma prognosis, but it only captures tumour size in one dimension. Adding a further measurement in a different axis has been shown to improve prognostic value. It seems reasonable that further prognostic value could be obtained by estimating the number of invasive melanoma cells using nuclear count. The aim of this study was to show proof of concept that nuclear count has prognostic value independent of BT. METHODS AND RESULTS: Melanoma cell nuclei were labelled with SRY-related HMG-box 10 (SOX10) protein, the sections scanned and StarDist machine-learning algorithm used to count nuclei in 102 cases of primary cutaneous melanoma. Prognostic value was assessed using survival analyses. Nuclear count correlated strongly with T category, BT and calculated tumour area (each P < 0.001), suggesting that it was a valid marker of melanoma burden. Nuclear count was a predictor for overall survival in univariable analysis [hazard ratio (HR) = 2.25, confidence interval (CI) = 1.66-3.06, P < 0.001] and multivariable analysis (HR = 2.60, CI = 1.59-4.24, P < 0.001). BT and ulceration were significant in univariable analyses, but not in multivariable models with nuclear count. Models containing nuclear count showed the best fit. Similar results were seen for melanoma-specific and metastasis-free survival. Nuclear count was able to stratify melanomas within a given T stage. CONCLUSIONS: This study demonstrated proof of concept that counting melanoma nuclei may be an improved measure of invasive tumour burden compared to BT. Future studies will need to refine methods of nuclear detection and also to confirm its prognostic value.

Comparison of the prognostic value of microscopically measured invasive width versus macroscopic width in cutaneous melanoma shows the superiority of microscopic invasive width measurement.

BACKGROUND: Invasive width, the distance between the most peripheral invasive melanoma cells on the section where Breslow thickness (BT) was measured, was recently identified as a prognostic feature. It is unclear whether a routine measurement is justified, given that macroscopic width is already included in many melanoma histopathology reports and may itself be a prognostic feature. This study sought to investigate this. METHODS: A retrospective cohort of 718 melanoma patients in which macroscopic width had been stated in the original histopathology report was used. Survival analysis was performed. RESULTS: Macroscopic and invasive widths were positively correlated (p < 0.001). Invasive width was typically smaller than the paired macroscopic width (median difference 3.7 mm, p < 0.001), a difference seen across all T groups. Both macroscopic and invasive widths were significantly associated with melanoma survival in Kaplan-Meier analysis, including overall survival, but invasive width survival curves were more widely separated. Both were significantly associated with outcome after correction for BT in Cox proportional hazards regression, but the models containing invasive width had a substantially better fit. CONCLUSIONS: This study shows that both macroscopic and invasive widths have prognostic values, but confirms that the latter is superior. It supports further investigation of this feature's prognostic value.

Global and mitosis-specific interobserver variation in mitotic count scoring and implications for malignant melanoma staging.

AIMS: Staging is the gold standard for predicting malignant melanoma outcome but changes in its criteria over time indicate ongoing evolution. One notable recent change from the 8th edition of the American Joint Committee on Cancer (AJCC) staging manual was removal of mitotic count. We explore the extent to which this feature is limited by interobserver error in order to find ways to improve its fitness for use should it be revisited in future staging versions. METHODS AND RESULTS: In a cohort of 476 patients with melanoma ≤1.0 mm, a mitotic count of 0 versus 1 was significant for metastasis-free survival, but not melanoma-specific or overall survival. In 10 melanomas that were 0.9-1.0 mm thick, the mitotic count intraclass correlation coefficient for histopathologists was 0.58 (moderate agreement). Uniquely, we also assessed agreement for specific putative mitotic figures, identifying precise reasons why specific mitotic figures qualified for scoring or elimination. A kappa score was 0.54 (moderate agreement). We also gathered data on other staging features. Breslow thickness had an intraclass correlation coefficient of 0.41 (moderate agreement) and there was a systematic difference between histopathologists among cases (P = 0.04). Every case had a range that crossed the AJCC8 0.8-mm pT1a/pT1b staging boundary. Ulceration was only identified in two of the 10 cases. For ulceration, kappa agreement score was 0.31 (fair). CONCLUSION: This study supports the removal of mitotic count from staging, but shows that its scoring is substantially affected by interobserver variation, suggesting that more prescriptive guidelines might have a beneficial impact on its prognostic value.

A case and literature review of orbital microcystic adnexal carcinoma.

Microcystic adnexal carcinoma (MAC) is a very rare and locally aggressive sweat gland tumour. MAC has been well reported presenting as a periocular cutaneous lesion, rarely with subsequent direct orbital invasion and only once as a primary orbital lesion. Local recurrence is frequent after primary surgical excision and the role of adjuvant radiotherapy is ill-defined. We describe a case of orbital MAC treated successfully with radiotherapy after incomplete margin clearance post exenteration surgery and review the associated literature.

5-Hydroxymethylcytosine is an independent predictor of survival in malignant melanoma.

Outcomes for melanoma patients vary within cancer stage. Prognostic biomarkers are potential adjuncts to provide more precise prognostic information. Simple, low-cost biomarker assays, such as those based on immunohistochemistry, have strong translational potential. 5-hydroxymethylcytosine (5 hmC) shows prognostic potential in melanoma but prior studies were small. We, therefore, analysed 5 hmC in a retrospective cohort to provide external validation of its prognostic value. Two hundred primary melanomas were evaluated for 5 hmC expression using immunohistochemistry. The primary objective was to assess the effect on overall survival while controlling for important confounders. Univariable and multivariable analyses were performed. REMARK guidelines were followed. The 5 hmC immunohistochemistry scoring showed very strong inter-observer agreement (ICC 0.88) and expression was significantly related to age, site, Breslow thickness, ulceration, mitotic rate, and stage. Kaplan-Meier analysis showed 5 hmC was associated with metastasis-free, melanoma-specific, and overall survival, P<0.0001 for each. In univariable Cox proportional hazards models, 5 hmC hazard ratios were significant and remained so in a multivariable model. A two-step cox model was created using stage and 5 hmC, as stage is the gold standard for clinical practice. The addition of 5 hmC produced significant improvement in the model and 5 hmC and stage were independent significant predictors. This is the largest study of the prognostic value of 5 hmC immunohistochemistry in melanoma. The 5 hmC scoring was easily and reproducibly performed and it was an independent predictor of metastasis-free survival, melanoma-specific survival, and overall survival. This work supports further development of 5 hmC as a prognostic biomarker and suggests that it could add more precision to American Joint Committee on Cancer staging.

Breslow density is a novel prognostic feature in cutaneous malignant melanoma.

AIMS: In 1970, Breslow described his eponymously named thickness measurement. No-one has sought to enhance the Breslow thickness (BT). The aim of this study was to demonstrate a proof of concept that the density of melanoma cells at the position where the BT is measured is a morphological prognostic biomarker, which we name the Breslow density (BD). The hypothesis was that the BD has prognostic value for overall survival (OS) and is independent of the BT. METHODS AND RESULTS: We analysed 100 cutaneous melanomas, and followed REMARK guidelines. The BD was the estimated percentage dermal area occupied by melanoma cells in a specified location. The BT and BD had a strong correlation (P = 2.1 × 10-11 ) but, despite this, they were independent prognostic factors for OS in Cox regression [BD hazard ratio (HR) 1.03, P = 0.001849; and BT HR 1.09, P = 0.000146]. This was corroborated by an independent effect on melanoma-specific survival. We assessed whether the BT and BD could be combined into a Breslow score. A prognostic index based on Cox regression coefficients was used, and this showed a marginal improvement in predicted 5-year survival as compared with the BT alone (area under the curve of 94.8% versus 96.7%). CONCLUSIONS: We show a proof of concept that the BD represents a novel morphological prognostic biomarker that is independent of the BT, and that there is potential to combine these into a Breslow score. Larger studies are needed to validate the BD, but the simplicity of this biomarker makes it a strong candidate for translation to clinical practice.

A new cause of lacrimal gland calcification: Retained metallic foreign bodies.

A 49-year-old male presented with a 4 month history of dysaesthesia in the left periorbital region. A CT scan showed a lacrimal gland mass with areas of dense calcification. Biopsies of the left lacrimal gland revealed a silver material with associated chronic granulomatous inflammation and secondary calcification. The histological specimen was sent for X-ray microanalysis. This confirmed the silver material to be aluminium. The metal fragments were subsequently discovered to be from a car aerial, which caused an orbital impaling injury 20 years prior to presentation. This is the first reported case of lacrimal gland calcification secondary to chronic metal foreign body exposure. The case is presented alongside literature reviews of lacrimal gland calcification and associated radiological findings.

microRNA-10b is a prognostic biomarker for melanoma.

Malignant melanoma is an aggressive form of skin cancer. Recently, drug therapy of advanced disease has been revolutionized by new agents. More therapeutic options, coupled with the desire to extend treatment to the adjuvant setting mean that prognostic biomarkers that can be assayed from formalin-fixed paraffin-embedded clinical would be valuable. microRNAs have potential to fill this need. We analyzed 377 microRNAs in 79 primary melanomas and 32 metastases using a split sample discovery strategy. From a discovery analysis using 40 thick primary melanomas (20 cases with metastasis and 20 controls without metastasis at 5 years), microRNA expression was measured by quantitative RT-PCR (QRT-PCR). MiR-10b emerged as a candidate prognostic microRNA. This was confirmed in an independent validation set of thick primary melanomas (20 cases with metastasis and 19 controls without metastasis at 5 years). In the combined discovery and validation cohorts (n=79), miR-10b expression showed a 3.7-fold increase in expression between cases and controls (P=0.005) and showed a trend of increasing expression between primary melanomas and their matched metastases (P<0.001). In situ hybridization showed expression was in melanoma cells and correlated with expression measured by QRT-PCR (P=0.0005). We used the combined discovery and validation samples to verify the prognostic value of additional candidate microRNAs identified from other studies, and proceeded to analyze miR-200b. We demonstrated that miR-10b and miR-200b showed independent prognostic value (P=0.002 and 0.047, respectively) in multivariable analysis alongside known clinico-pathological prognostic features (eg, Breslow thickness) using a Cox proportional hazards regression model. Furthermore, the addition of these microRNAs to the clinico-pathological features led to an improved regression model with better identification of aggressive thick melanomas. Taken together, these data suggest that miR-10b is a new prognostic microRNA for melanoma and that there could be a place for microRNA analysis in stratifying melanoma for therapy.

Redox modulation of oxidatively-induced DNA damage by ascorbate enhances both in vitro and ex-vivo DNA damage formation and cell death in melanoma cells.

Elevated genomic instability in cancer cells suggests a possible model-scenario for their selective killing via the therapeutic delivery of well-defined levels of further DNA damage. To examine this scenario, this study investigated the potential for redox modulation of oxidatively-induced DNA damage by ascorbate in malignant melanoma (MM) cancer cells, to selectively enhance both DNA damage and MM cell killing. DNA damage was assessed by Comet and ɣH2AX assays, intracellular oxidising species by dichlorofluorescein fluorescence, a key antioxidant enzymatic defence by assessment of catalase activity and cell survival was determined by clonogenic assay. Comet revealed that MM cells had higher endogenous DNA damage levels than normal keratinocytes (HaCaT cells); this correlated MM cells having higher intracellular oxidising species and lower catalase activity, and ranked with MM cell melanin pigmentation. Comet also showed MM cells more sensitive towards the DNA damaging effects of exogenous H2O2, and that ascorbate further enhanced this H2O2-induced damage in MM cells; again, with MM cell sensitivity to induced damage ranking with degree of cell pigmentation. Furthermore, cell survival data indicated that ascorbate enhanced H2O2-induced clonogenic cell death selectively in MM cells whilst protecting HaCaT cells. Finally, we show that ascorbate serves to enhance the oxidising effects of the MM therapeutic drug Elesclomol in both established MM cells in vitro and primary cell cultures ex vivo. Together, these results suggest that ascorbate selectively enhances DNA damage and cell-killing in MM cells. This raises the option of incorporating ascorbate into clinical oxidative therapies to treat MM.

Prognostic tissue markers in melanoma.

Prognostic tissue markers in melanoma Prognosis for patients diagnosed with cutaneous melanoma is currently based upon histopathological features alone, although tumours which are morphologically similar can behave differently. Numerous putative biomarkers have been identified in an attempt to aid prognostication for primary melanoma, using methods which include immunhistochemistry, polymerase chain reaction (PCR), array comparative genomic hybridization (CGH) and gene expression arrays. Despite this wide body of research, no biomarkers for prognosis in melanoma have been translated or are close to translation into clinical practice. In this review selected prognostic biomarkers are evaluated and the factors influencing successful biomarker translation, including phases of biomarker development and study design, are explored in an attempt to highlight the current gap between prognostic melanoma biomarker research and clinical translation.

Detection of copy number changes in DNA from formalin fixed paraffin embedded tissues using paralogue ratio tests.

The purpose of this study was to evaluate whether paralogue ratio tests (PRT) using real-time PCR can accurately determine the DNA copy number (CN) using formalin fixed paraffin embedded (FFPE) tissue. Histopathology diagnostic archives are an enormous resource of FFPE tissue, but extracted DNA is of poor quality and may be unsuitable for CN assessment, thus representing a missed opportunity for studies of genetic association and somatic change in cancer in large cohorts of easily accessible samples. Assays with paralogues on chromosomes 18 and 20 (18|20 PRT) and chromosomes 13 and X (13|X PRT) were tested using archived FFPE pathology samples with known CN, including tonsil, placentae, and FFPE melanoma cell lines. The assay proved accurate over the dynamic range from 1:1 to 1:3 and gave precise results when repeated four times over several weeks. The precision of the assay was marginally reduced once the CT value for 10 ng of FFPE DNA increased above 30 cycles, reflecting importance of DNA quality. The assays distinguished changes in CN ratio with high sensitivity and specificity. The 13|X PRT could detect cells with distinct genotypes microdissected from within the same FFPE sample. Therefore, PRTs are suitable for analyzing CN in FFPE tissues.

The Width of Invasion in Malignant Melanoma Is a Novel Prognostic Feature That Accounts for Outcome Better Than Breslow Thickness.

Breslow thickness (BT) is the cornerstone of malignant melanoma staging. However, to our knowledge no-one has ever assessed the horizontal width of invasion, measured microscopically, as a prognostic feature. This was investigated as a prognostic feature in this study. A retrospective cohort of 1329 melanoma cases was collected from patients presenting to a UK teaching hospital from January 1, 2004, to December 31, 2014. The main outcome was overall survival (OS). We found that width was associated with OS in multivariable analysis (hazard ratio=1.05, 95% confidence interval: 1.03-1.07, P<0.001) and was similarly significant for melanoma-specific survival and metastasis-free survival. Its presence rendered BT nonsignificant. The width was significantly associated with OS after adjustment for American Joint Committee on Cancer (AJCC), version 8 clinical tumor stage (hazard ratio=1.05, 95% confidence interval: 1.03-1.07, P<0.001), and bootstrap validation showed only slight model optimism. Similar associations were seen for melanoma-specific survival and metastasis-free survival. However, the combination of invasive width and BT did not account for the outcome as well as another novel histologic feature, tumor area, which was measured using the calculated tumor area method. In conclusion, this study is the first investigation of a novel histologic feature, invasive melanoma width, and demonstrates its strong independent association with outcome.

WNT5A expression increases during melanoma progression and correlates with outcome.

PURPOSE: Wnt ligands play a major role in development and are important in cancer. Expression microarray analysis correlates one member of this family, WNT5A, to a subclass of melanomas with increased motility and invasion. There are no large studies of clinical samples primarily addressing the importance of WNT5A in melanoma progression or outcome. Therefore, this study aimed to assess the protein expression of WNT5A during melanoma progression and its effect on outcome. EXPERIMENTAL DESIGN: Expression of WNT5A was determined in a series of 59 primary melanomas with matched metastases. To provide a benchmark of progression against which to assess WNT5A, expression of p16(ink4a) was analyzed, as this has been previously well documented in melanoma. The effect of WNT5A protein expression on outcome was assessed in 102 melanomas. RESULTS: Cytoplasmic WNT5A showed a trend of increasing expression with melanoma progression (P = 0.013), whereas there was diminishing p16(ink4a) expression (P = 0.006). Nevi showed relatively strong WNT5A expression. Strong cytoplasmic WNT5A was an independent risk factor for reduced metastasis-free and overall survival in multivariate analysis (P = 0.001 and 0.003, respectively). CONCLUSION: Cytoplasmic WNT5A increases with melanoma progression and strong expression is associated with poor outcome.

Development and Initial Validation of Calculated Tumor Area as a Prognostic Tool in Cutaneous Malignant Melanoma.

IMPORTANCE: Breslow thickness is a 1-dimensional surrogate prognostic feature for tumor size, yet tissue sections have 2 dimensions. Therefore, a 2-dimensional feature, calculated tumor area (CTA), was devised. OBJECTIVE: To determine CTA precision and prognostic value. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort of patients with cutaneous melanoma presented to the Leicester and Nottingham National Health Service hospital trusts in the United Kingdom. Eligible patients in the Leicester development sample had available primary tumor tissue; a diagnosis from January 1, 2004, through December 31, 2011; invasive disease; and Leicestershire residency. Patients in the Nottingham validation sample had an anonymized spreadsheet with primary melanoma diagnosed from January 1, 2003, through December 31, 2005, or from January 1, 2008, through December 31, 2010. From a starting population of 1463 patients in both data sets, a total of 224 (15.3%) were excluded to yield a study population of 1239. Data were analyzed from April 30, 2018, through January 10, 2019. INTERVENTION: An observational analysis of the prognostic value of CTA in patients with cutaneous melanoma. MAIN OUTCOMES AND MEASURES: Independent association of CTA with melanoma-specific survival and confounding effect of CTA on Breslow thickness in survival analysis. RESULTS: A total of 1239 patients with melanoma were assessed, including 649 (52.4%) women, with a median age of 60 years (interquartile range, 47-71 years). An intraclass correlation coefficient for CTA on 13 cases was 0.99. In 918 patients in the Leicester cohort, CTA was an independent prognostic factor in Cox proportional hazards regression models after adjusting for Breslow thickness, age, sex, ulcer, mitotic rate, and microsatellites (hazard ratio [HR], 1.87; 95% CI, 1.49-2.34; P < .001). Validation in 321 patients in the Nottingham cohort showed an HR of 1.55 (95% CI, 1.15-2.09; P = .005) and in the combined 1239 cases, an HR of 1.70 (95% CI, 1.43-2.03; P < .001). Breslow thickness was significant in multivariable analysis only when CTA was not in the model. The relative importance of CTA was shown by its retention in all 100 bootstrap multivariable models with backward selection, whereas Breslow thickness was retained in only 53. Melanomas stratified by CTA showed wider separation of survival curves than those stratified by Breslow thickness using the American Joint Committee on Cancer Staging Manual, 8th Edition (HRs, 1.00 to 41.46 vs 1.00 to 36.95, respectively), and the model with CTA categories had a Bayesian information criterion difference of 13.9 compared with T category, indicating substantially better fit. This model had a Harrell C index of 83.7%, and bootstrap analysis showed little evidence of model optimism, with a corrected calibration slope of 0.99. CONCLUSIONS AND RELEVANCE: This study provides a novel microscopic feature, CTA, with evidence of its independent prognostic value. This evidence suggests that CTA should be a priority for further study.

Breslow Density Is a Novel Prognostic Feature That Adds Value to Melanoma Staging.

Histomorphologic prognostic biomarkers that can be measured using only an hematoxylin and eosin stain are very attractive because they are simple and cheap. We conceived an entirely novel biomarker of this type, the Breslow density (BD), which measures invasive melanoma cell density at the site where Breslow thickness (BT) is measured. This study assessed BD's prognostic value. In this study, BD was measured in 1329 melanoma patients. Measurement accuracy and precision was assessed using intraclass correlation coefficient (ICC). Survival was assessed with a primary end-point of melanoma-specific survival (MSS) and also overall survival and metastasis-free survival. We found that BD measurement was accurate compared with gold standard image analysis (ICC, 0.84). Precision was excellent for 3 observers with different experience (ICC, 0.93) and for an observer using only written instructions (ICC, 0.93). BD was a highly significant predictor in multivariable analysis for overall survival, MSS, and metastasis-free survival (each, P<0.001) and it explained MSS better than BT, but BT and BD together had best explanatory capability. A BD cut point of ≥65% was trained in 970 melanomas and validated in 359. This cut point showed promise as a novel way to upstage melanoma from T stage "a" to "b." BD was combined with BT to create a targeted burden score. This was a validated as an adjunct to American Joint Committee on Cancer stage. In summary, BD can be measured accurately and precisely. It demonstrated independent prognostic value and explained MSS better than BT alone. Notably, we demonstrated ways that BD could be used with American Joint Committee on Cancer version 8 staging.

Compromised vitamin D receptor signalling in malignant melanoma is associated with tumour progression and mitogen-activated protein kinase activity.

The aims of this study were to investigate, in cutaneous malignant melanoma (MM), the integrity of nuclear vitamin D receptor (VDR) signalling, as implied by VDR subcellular location; to investigate the relationship between VDR and tumour progression and the inhibitory effect on VDR by mitogen-activated protein kinase (MAPK) overactivity. Archived tissue from 34 benign melanocytic naevi, 149 MMs and 44 matched metastases were stained by immunohistochemistry for VDR and a subset of primary MMs were stained for phosphorylated-extracellular signal-regulated kinase as a marker of MAPK activity. MM cell lines were investigated to show the subcellular location of VDR and cell viability in response to ligand±MAPK inhibitor. Benign melanocytic naevi showed mainly a strong nuclear VDR staining in contrast to MM where decreased nuclear and emergent cytoplasmic VDRs were associated with malignant progression in terms of dermal invasion and metastasis. MMs that retained exclusive nuclear VDR at the tumour base did not metastasize, a potentially important prognostic indicator. Decreased nuclear VDR correlated with increased cytoplasmic staining, suggesting the failure of nuclear entry as a primary cause of defective VDR signalling in MM. The histological subset analysis and MM cell line studies confirmed the inhibitory effect of MAPK activity on VDR signalling, but the pattern of VDR subcellular localization suggested failure of VDR nuclear entry as a primary effect of MAPK activity rather than direct inhibition of VDR-regulated transcription. Furthermore, high MAPK activity in tumours expressing cytoplasmic VDR was associated with worsened prognosis.

Cutaneous melanoma subtypes show different BRAF and NRAS mutation frequencies.

PURPOSE: BRAF mutations are present in two thirds of cutaneous melanomas and many of the rest have NRAS mutations. However, cutaneous melanoma is a heterogeneous disease with many clinicopathologic subtypes. Of these, the majority fits into four categories: superficial spreading, nodular, lentigo maligna, and acral lentiginous melanoma (ALM). Thus far, there is very limited data combining BRAF and NRAS mutation analysis to explore differences between cutaneous melanoma subtypes. The aim of this study was to address this issue. EXPERIMENTAL DESIGN: The frequency of BRAF and NRAS hotspot mutations, in exons 15 and 2, respectively, was assessed in 59 cutaneous melanomas comprising superficial spreading, nodular, lentigo maligna, and ALM using single-strand conformational polymorphism and RFLP-PCR analysis. RESULTS: Only 2 of 21 (9.5%) ALM showed BRAF exon 15 mutation compared with 9 of 14 (64.3%) superficial spreading malignant melanomas, 4 of 11 (36.4%) nodular melanomas, and 7 of 13 (53.4%) lentigo maligna melanomas (P < 0.01). However, our key finding is that the combined analysis of BRAF exon 15 and NRAS exon 2 showed that there were no significant differences in the overall mutation frequency between subtypes. In particular, 9 of 19 (47.4%) ALM without BRAF exon 15 mutation had an NRAS exon 2 mutation. CONCLUSIONS: We show that the overall BRAF/NRAS frequency in mutation hotspots is not significantly different among cutaneous melanoma subtypes. These data show that mitogen-activated protein kinase pathway activation may be important in all major subtypes of cutaneous melanoma, although the mechanism by which this is achieved varies.

A Novel Numerical Scoring System for Melanoma Tumor-infiltrating Lymphocytes Has Better Prognostic Value Than Standard Scoring.

The purpose of this study was to evaluate the prognostic value of tumor-infiltrating lymphocytes (TILs) in melanoma and to determine whether a simpler numerical scoring system would be more effective. In total, 655 patients presenting to a UK teaching hospital with primary invasive melanoma were analyzed. TILs were rescored using the standard Clark's method and univariable and multivariable analyses of the effect of TILs on overall survival (OS), disease-specific survival (DSS), and metastasis-free survival (MFS) was assessed using Cox regression. In total, 30 (5%) melanomas showed absent, 464 (71%) nonbrisk, and 161 (24%) brisk TILs. There was a statistically significant relationship between TILs and Breslow thickness, age, melanoma type, mitotic rate, and histologic regression. TIL grade was a significant predictor of MFS in multivariable analysis (hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.25-0.77) but was not significant for OS or DSS. By contrast, when a simple numerical TIL percentage score was used this was a strong predictor of OS (HR, 0.55; 95% CI, 0.38-0.78), DSS (HR, 0.25; 95% CI, 0.14-0.44), and MFS (HR, 0.32; 95% CI, 0.21-0.51) in multivariable analysis. The percentage TIL score was also significant when adjusted for the prognostic gold standard, American Joint Committee on Cancer stage: OS (HR, 0.66; 95% CI, 0.46-0.95), DSS (HR, 0.33; 95% CI, 0.19-0.60), and MFS (HR, 0.41; 95% CI, 0.26-0.65). The TIL percentage score was subsequently validated in new cases. In summary, this study strongly confirms that higher amounts of TILs are associated with better prognosis and in addition demonstrates the value of a simplified numerical TIL scoring system.

MicroRNA-21 expression and its pathogenetic significance in cutaneous melanoma.

Identification of prognostic biomarkers is timely for melanoma as clinicians seek ways to stratify patients for molecular therapy. MicroRNAs are promising as tissue biomarkers because they can be assayed directly from formalin-fixed paraffin-embedded clinical samples. We previously reported that microRNA-21 (miR-21) was strongly expressed in melanoma relative to naevi and now sought to further assess the significance of this by assessing its relationship with its putative target, PTEN. Clinical melanoma samples were analysed by immunohistochemical analysis for PTEN, stem-loop qRT-PCR for miR-21 and PCR for BRAF/NRAS mutation status. Cell lines were investigated for the effect of anti-miR-21 on PTEN. A total of 81 clinical melanocytic tumour samples were investigated, with uniformly high PTEN expression in the nucleus and cytoplasm of naevi and with preferential loss of PTEN expression in the nucleus of melanoma cells. miR-21 expression was inversely associated with nuclear PTEN expression but not with cytoplasmic PTEN expression. An anti-miR-21 preferentially altered nuclear PTEN in melanoma cell lines. The presence of a BRAF or NRAS mutation had no significant effect on miR-21 expression. These data suggest miR-21 may exert an oncogenic effect in melanoma by favouring redistribution of PTEN to the nucleus.