Richard A. Scolyer

Prognostic and Clinicopathologic Associations of Oncogenic BRAF in Metastatic Melanoma

PURPOSE To assess the frequency and type of oncogenic BRAF mutations in metastatic melanoma and correlate BRAF status with clinicopathologic features and outcome. PATIENTS AND METHODS Consecutive BRAF-tested Australian patients with metastatic melanoma (n = 197) were observed prospectively. A comprehensive range of clinicopathologic variables were correlated with BRAF mutation status, and a survival analysis was conducted. RESULTS Forty-eight percent of patients had a BRAF mutation; 70 patients (74%) had V600E, 19 (20%) had V600K, and six (6%) had other genotypes. Other than age at diagnosis of distant metastasis (median age, 56 v 63 years for BRAF-mutant v BRAF wild-type patients, respectively; P < .001), there was no significant difference in clinical features of patients with metastatic melanoma by mutation status. Features of the antecedent primary melanoma significantly associated with a BRAF mutation (P < .05) were histopathologic subtype, presence of mitoses, single or occult primary melanoma, truncal location, and age at diagnosis of primary tumor ≤ 50 years. The interval from diagnosis of first-ever melanoma to distant metastasis was not significantly different between BRAF-mutant and BRAF wild-type patients; however, the median survival of patients with newly diagnosed metastatic melanoma was 5.7 months for BRAF-mutant patients not treated with a BRAF inhibitor, 8.5 months for BRAF wild-type patients, and not reached for BRAF-mutant patients treated with a BRAF inhibitor. CONCLUSION V600K mutations comprised 20% of BRAF mutations. Characteristics of the antecedent primary melanoma and age at diagnosis differed in BRAF-mutant and BRAF wild-type patients. The presence of mutant BRAF had no impact on the disease-free interval from diagnosis of first-ever melanoma to first distant metastasis; however, it may have impacted survival thereafter.

Melanoma whole-exome sequencing identifies V600E B-RAF amplification-mediated acquired B-RAF inhibitor resistance

The development of acquired drug resistance hampers the long-term success of B-RAF inhibitor (B-RAFi) therapy for melanoma patients. Here we show V600EB-RAF copy number gain as a mechanism of acquired B-RAFi resistance in four out of twenty (20%) patients treated with B-RAFi. In cell lines, V600EB-RAF over-expression and knockdown conferred B-RAFi resistance and sensitivity, respectively. In V600EB-RAF amplification-driven (vs. mutant N-RAS-driven) B-RAFi resistance, ERK reactivation is saturable, with higher doses of vemurafenib down-regulating pERK and re-sensitizing melanoma cells to B-RAFi. These two mechanisms of ERK reactivation are sensitive to the MEK1/2 inhibitor AZD6244/selumetinib or its combination with the B-RAFi vemurafenib. In contrast to mutant N-RAS-mediated V600EB-RAF bypass, which is sensitive to C-RAF knockdown, V600EB-RAF amplification-mediated resistance functions largely independently of C-RAF. Thus, alternative clinical strategies may potentially overcome distinct modes of ERK reactivation underlying acquired B-RAFi resistance in melanoma.

Selective BRAF Inhibitors Induce Marked T-cell Infiltration into Human Metastatic Melanoma

Purpose: To evaluate the effects of treatment with the potent mutant BRAF inhibitors GSK2118436 or vemurafenib (PLX4720) on immune responses to metastatic melanoma in tissues taken before and after treatment. Experimental Design: Thirty-seven tumor biopsies were collected from 15 patients with unresectable American Joint Committee on Cancer stage III or IV melanoma immediately before and approximately 7 days after the commencement of BRAF inhibitor treatment and at the time of tumor progression. Immunohistochemical staining was carried out on the biopsies using specific antibodies for CD8, CD4, CD20, CD1a, and Granzyme B. Results: Tumor infiltration by CD4+ and CD8+ lymphocytes increased markedly following BRAF inhibitor treatment (both ρ = 0.015). There was a correlation between the degree of tumor infiltration by CD8+ and Granzyme B–expressing lymphocytes in post–BRAF inhibitor–treated biopsies (r = 0.690 and ρ = 0.013). Increased intratumoral CD8+ lymphocyte expression was correlated with a reduction in tumor size and an increase in necrosis in posttreatment biopsies (r = −0.793, ρ = 0.011; and r = 0.761, ρ = 0.004, respectively). Conclusions: The increase in tumor-infiltrating lymphocytes induced by treatment with BRAF inhibitors provides strong support for conducting trials that combine BRAF inhibitors with immunotherapy in the hope of prolonging clinical responses. Clin Cancer Res; 18(5); 1386–94. ©2011 AACR.

Tumor mitotic rate is a more powerful prognostic indicator than ulceration in patients with primary cutaneous melanoma: an analysis of 3661 patients from a single center.

The current study was performed to determine whether tumor mitotic rate (TMR) is a useful, independent prognostic factor in patients with localized cutaneous melanoma.

Distinguishing Clinicopathologic Features of Patients with V600E and V600K BRAF-Mutant Metastatic Melanoma

Purpose: Certain clinicopathologic features correlate with BRAF mutation status in melanoma including younger age and primary subtype. This study sought to determine the BRAF mutation status by age-decade and whether BRAF-mutant genotypes correlated with clinicopathologic features and outcome in patients with metastatic melanoma. Methods: A prospectively assembled cohort of Australian patients were followed from diagnosis of metastatic melanoma (N = 308). Clinicopathologic variables were correlated with BRAF mutational status, genotype, and survival. Results: Forty-six percent of patients had a BRAF mutation; 73% V600E, 19% V600K, and 8% other genotypes. An inverse relationship existed between BRAF mutation prevalence and age-decade (P < 0.001). All patients <30 years and only 25% ≥70 years had BRAF-mutant melanoma. Amongst BRAF-mutant melanoma, the frequency of non-V600E genotypes (including V600K) increased with increasing age. Non-V600E genotypes comprised <20% in patients <50 years and >40% in those ≥70 years. A higher degree of cumulative sun-induced damage correlated with V600K but not V600E melanoma (P = 0.002). The disease-free interval from diagnosis of primary melanoma to first distant metastasis was shorter for patients with V600K compared with V600E melanoma (17.4 vs. 39.2 months, P = 0.048), with no difference in survival thereafter. In patients BRAF tested at diagnosis of metastatic melanoma, one year survival from diagnosis of metastasis was significantly longer for patients with BRAF-mutant melanoma treated with an inhibitor (83%), than those not treated with an inhibitor (29%, P < 0.001), or patients with BRAF wild-type melanoma (37%, P < 0.001). Conclusion: Different genotypes exist within BRAF-mutant metastatic melanoma, representing biologically and clinically discrete subtypes, suggesting distinct etiology and behavior. Clin Cancer Res; 18(12); 3242–9. ©2012 AACR.

Human papillomavirus positivity predicts favourable outcome for squamous carcinoma of the tonsil

Mutations in the p53 and retinoblastoma (pRb) pathways associated with the use of tobacco and alcohol are common in squamous cell carcinoma (SCC) of the head and neck. Cell cycle proteins are also affected by human papillomavirus (HPV), which may also have an aetiological role in cancers at particular sites, most notably the tonsil. Attempts to identify prognostic molecular markers in head and neck cancers have met with conflicting results, but few studies have been undertaken with tumours of known HPV status at a single anatomic site. In our study 86 tonsil cancers were analysed for HPV status by sequence analysis of polymerase chain reaction products and for the expression of cell cycle proteins (p53, p21CIP1/WAF1, pRb, p16INK4A, cyclin D1 and p27KIP1) by immunohistochemistry. The HPV status could be established in 67 of the tumours. Thirty‐one (46%) of these were HPV‐positive, predominantly (28/31) for HPV16. Findings were related to tumour recurrence and patient survival. None of the cell cycle proteins independently predicted recurrence or survival. Patients with HPV‐positive tumours, however, were significantly less likely (p < 0.05) to have recurrence or to die of disease than those with HPV‐negative tumours, after adjusting for the effects of the cell cycle proteins, clinical stage, pathological node status, tumour grade, age, gender and treatment. These findings support the concept that HPV‐positive tonsil cancers may be a distinct biological group with less aggressive characteristics. Screening of tonsil cancers for HPV DNA may help optimise treatment and provide more accurate prognostic information.

Immunohistochemistry Is Highly Sensitive and Specific for the Detection of V600E BRAF Mutation in Melanoma

This study investigated the sensitivity and specificity of immunohistochemical (IHC) analysis using an anti-BRAF antibody to detect the presence of the BRAF V600E mutation in patients with metastatic melanoma. A total of 100 patients with American Joint Committee on Cancer stage IIIC unresectable or stage IV melanoma and who underwent tumor DNA BRAF mutation testing were selected. Paraffin-embedded, formalin-fixed melanoma biopsies were analyzed for the BRAF mutation status by independent, blinded observers using both conventional DNA molecular techniques and IHC with the novel BRAF V600E mutant-specific antibody, VE1. The antibody had a sensitivity of 97% (37/38) and a specificity of 98% (58/59) for detecting the presence of a BRAF V600E mutation. Of the BRAF-mutated cases, none of the non-V600E cases (including V600K) stained positive with the antibody (0/11). There were 5 cases with discordant BRAF mutation results. Additional molecular analysis confirmed the immunohistochemically obtained BRAF result in 3 cases, suggesting that the initial molecular testing results were incorrect. Two of these patients would not have received a BRAF inhibitor on the basis of the initial false-negative mutation testing result. Two cases remained discordant. The reported IHC method is an accurate, rapid, and cost-effective method for detecting V600E BRAF mutations in melanoma patients. Clinical use of the V600E BRAF antibody should be a valuable supplement to conventional mutation testing and allow V600E mutant metastatic melanoma patients to be triaged rapidly into appropriate treatment pathways.

BRAF Inhibitor Resistance Mechanisms in Metastatic Melanoma: Spectrum and Clinical Impact

Purpose: Multiple BRAF inhibitor resistance mechanisms have been described, however, their relative frequency, clinical correlates, and effect on subsequent therapy have not been assessed in patients with metastatic melanoma. Experimental Design: Fifty-nine BRAFV600-mutant melanoma metastases from patients treated with dabrafenib or vemurafenib were analyzed. The genetic profile of resistance mechanisms and tumor signaling pathway activity was correlated with clinicopathologic features and therapeutic outcomes. Results: Resistance mechanisms were identified in 58% progressing tumors and BRAF alterations were common. Gene expression analysis revealed that mitogen-activated protein kinase (MAPK) activity remained inhibited in 21% of resistant tumors, and the outcomes of patients with these tumors were poor. Resistance mechanisms also occurred in pretreatment biopsies and heterogeneity of resistance mechanisms occurred within patients and within tumors. There were no responses to subsequent targeted therapy, even when a progressing tumor had a resistance mechanism predicted to be responsive. Conclusions: Selecting sequential drugs based on the molecular characteristics of a single progressing biopsy is unlikely to provide improved responses, and first-line therapies targeting multiple pathways will be required. Clin Cancer Res; 20(7); 1965–77. ©2014 AACR.

Tumor-Infiltrating Lymphocyte Grade Is an Independent Predictor of Sentinel Lymph Node Status and Survival in Patients With Cutaneous Melanoma

PURPOSE To determine whether density and distribution of tumor-infiltrating lymphocytes (TILs; TIL grade) is an independent predictor of sentinel lymph node (SLN) status and survival in patients with clinically localized primary cutaneous melanoma. METHODS From the Melanoma Institute Australia database, 1,865 patients with a single primary melanoma ≥ 0.75 mm in thickness were identified. The associations of clinical and pathologic factors with SLN status, recurrence-free survival (RFS), and melanoma-specific survival (MSS) were analyzed. RESULTS The majority of patients had either no (TIL grade 0; 35.4%) or few (TIL grade 1; 45.1%) TILs, with a minority showing moderate (TIL grade 2; 16.3%) or marked (TIL grade 3; 3.2%) TILs. Tumor thickness, mitotic rate, and Clark level were inversely correlated with TIL grade (each P < .001). SLN biopsy was performed in 1,138 patients (61.0%) and was positive in 252 (22.1%). There was a significant inverse association between SLN status and TIL grade (SLN positivity rates for each TIL grade: 0, 27.8%; 1, 20.1%; 2, 18.3%; 3, 5.6%; P < .001). Predictors of SLN positivity were decreasing age (P < .001), decreasing TIL grade (P < .001), ulceration (P = .003), increasing tumor thickness (P = .01), satellitosis (P = .03), and increasing mitoses (P = .03). The 5-year MSS and RFS rates were 83% and 76%, respectively (median follow-up, 43 months). Tumor thickness (P < .001), ulceration (P < .001), satellitosis (P < .001), mitotic rate (P = .003), TIL grade (P < .001), and sex (P = .01) were independent predictors of MSS. Patients with TIL grade 3 tumors had 100% survival. CONCLUSION TIL grade is an independent predictor of survival and SLN status in patients with melanoma. Patients with a pronounced TIL infiltrate have an excellent prognosis.

Adjuvant radiotherapy versus observation alone for patients at risk of lymph-node field relapse after therapeutic lymphadenectomy for melanoma: a randomised trial

BACKGROUND The use of radiotherapy after therapeutic lymphadenectomy for patients with melanoma at high risk of further lymph-node field and distant recurrence is controversial. Decisions for radiotherapy in this setting are made on the basis of retrospective, non-randomised studies. We did this randomised trial to assess the effect of adjuvant radiotherapy on lymph-node field control in patients who had undergone therapeutic lymphadenectomy for metastatic melanoma in regional lymph nodes. METHODS This randomised controlled trial included patients from 16 hospitals in Australia, New Zealand, the Netherlands, and Brazil. To be eligible for this trial, patients had to be at high risk of lymph-node field relapse, judged on the basis of number of nodes involved, extranodal spread, and maximum size of involved nodes. After lymphadenectomy, randomisation was done centrally by computer and patients assigned by telephone in a ratio of 1:1 to receive adjuvant radiotherapy of 48 Gy in 20 fractions or observation, with institution, lymph-node field, number of involved nodes, maximum node diameter, and extent of extranodal spread as minimisation factors. Participants, those giving treatment, and those assessing outcomes were not masked to treatment allocation. The primary endpoint was lymph-node field relapse (as a first relapse), analysed for all eligible patients. The study is registered at ClinicalTrials.gov, number NCT00287196. The trial is now closed and follow-up discontinued. FINDINGS 123 patients were randomly allocated to the adjuvant radiotherapy group and 127 to the observation group between March 20, 2002, and Sept 21, 2007. Two patients withdrew consent and 31 had a major eligibility infringement as decided by the independent data monitoring committee, resulting in 217 eligible for the primary analysis (109 in the adjuvant radiotherapy group and 108 in the observation group). Median follow-up was 40 months (IQR 27-55). Risk of lymph-node field relapse was significantly reduced in the adjuvant radiotherapy group compared with the observation group (20 relapses in the radiotherapy group vs 34 in the observation group, hazard ratio [HR] 0·56, 95% CI 0·32-0·98; p=0·041), but no differences were noted for relapse-free survival (70 vs 73 events, HR 0·91, 95% CI 0·65-1·26; p=0·56) or overall survival (59 vs 47 deaths, HR 1·37, 95% CI 0·94-2·01; p=0·12). The most common grade 3 and 4 adverse events were seroma (nine in the radiotherapy group vs 11 in the observation group), radiation dermatitis (19 in the radiotherapy group), and wound infection (three in the radiotherapy group vs seven in the observation group). INTERPRETATION Adjuvant radiotherapy improves lymph-node field control in patients at high risk of lymph-node field relapse after therapeutic lymphadenectomy for metastatic melanoma. Adjuvant radiotherapy should be discussed with patients at high risk of relapse after lymphadenectomy. FUNDING National Health and Medical Research Council of Australia, Cancer Australia, Melanoma Institute Australia, Cancer Council of South Australia.