Nancy Uhrhammer1, Jacques-Olivier Bay1, Susan Perlman2, Richard A Gatti3 1. Centre Jean Perrin, Departement d'Oncologie Moleculaire, Clermont-Ferrand, France 2. UCLA School of Medicine, Dept of Neurology, Los Angeles, CA 90095 3. UCLA School of Medicine, Dept of Pathology, Los Angeles, CA 90095 April 2000; updated April 2002. Ataxia-telangiectasia (A-T) is an autosomal recessive multisystem disorder with early-onset cerebellar ataxia as its defining neurologic feature. It is the most common, recessively inherited, cerebellar ataxia in children under 5 years of age, with a prevalence of 1/40,000 to 1/100,000 live births [Swift 1985]. The accompanying extra-neural features aid in its clinical diagnosis and include conjunctival and cutaneous telangiectases, elevated levels of serum alphafetoprotein, chromosome aberrations, immunodeficiency with recurrent sinopulmonary infection, cancer susceptibility, and radiation hypersensitivity. Since identification of the causative gene, ATM (for Ataxia-Telangiectasia mutated), on chromosome 11q22-q23 [Gatti 1988, Savitsky 1995], the molecular basis of certain aspects of the disease have become clearer, though others remain to be elucidated [Gatti 1998, Meyn 1997, Shiloh 1996]. Note: see also cards on genes ATM, and NBS1 , and on cancer prone diseases Ataxia telangectasia and Nijmegen breakage syndrome CLINICAL FEATURES Neurologic Features Progressive cerebellar ataxia is almost always the presenting symptom and becomes apparent as early as the first year of life. Truncal and gait ataxia are slowly and steadily progressive, although between the ages of 2 and 5 years normal development of motor skills may temporarily mask this decline. This cerebellar degeneration typically leads to wheelchair dependence by the second decade. Migration abnormalities of prenatal Purkinje cell (PC) as well as post-natal PC degeneration have been seen [Vinters 1985], with thinning of the molecular and granule cell layers and minor changes in dentate and olivary nuclei and medullary tracts. Oculomotor abnormalities may also be seen. The typical patient with A-T is of normal intelligence, although the motor abnormalities make formal psychometric testing and standard learning programs difficult. Telangiectasia Telangiectases appear an average of two to four years after onset of the neurologic syndrome and are progressive. They are composed of dilated capillaries in the conjunctiva, and, later, on the ears, over the bridge of the nose, in the antecubital fossae, behind the knees, or more diffusely. They do not occur on internal organs nor are they generally associated with bleeding problems. Cancer Risk

BRAF and NRAS mutation status does not influence survival in metastatic melanoma.

Merkel cell carcinoma is an aggressive, radiosensitive cutaneous neuroendocrine tumour. In this review, the roles of radiation therapy and chemoradiation in the management of Merkel cell carcinoma are described and discussed, and guidelines for patient management are presented. Radiation treatment may be indicated for definitive (> 55 Gy) or adjuvant (> 50 Gy) treatment of the primary tumour site and for prophylactic (> 50 Gy), adjuvant (> 50 Gy) or definitive (> 55 Gy) treatment of the regional lymph node field. If a patient presents with positive margins after initial biopsy or resection, definitive radiation therapy or chemoradiation may be an alternative to further surgery and, importantly, results in less delay than re-resection followed by adjuvant radiation treatment. Given the rarity of this tumour, patients should be enrolled on prospective databases and clinical trials, and managed in a multidisciplinary clinical setting wherever possible.

TMR is an important independent predictor of survival for melanoma patients. If confirmed by studies from other centers, it has the potential to further improve the accuracy of melanoma staging, as well as to define more rigidly the risk categories for patients entering clinical trials.

A histopathologic excision margin of 8 mm or more (corresponding to a ≥1 cm surgical excision margin) combined with SLN biopsy (followed by an immediate completion lymph node dissection if positive) provided T3 melanoma patients with optimum local, regional, and distant disease control and resulted in enhanced melanoma-specific survival.

Outcomes for melanoma patients with stage III disease differ widely even within the same subcategory. Molecular signatures that more accurately predict prognosis are needed to stratify patients according to risk. Proteomic analyses were used to identify differentially abundant proteins in extracts of surgically excised samples from patients with stage IIIc melanoma lymph node metastases. Analysis of samples from patients with poor (n = 14, <1 yr) and good (n = 19, >4 yr) survival outcomes identified 84 proteins that were differentially abundant between prognostic groups. Subsequent selected reaction monitoring analysis verified 21 proteins as potential biomarkers for survival. Poor prognosis patients are characterized by increased levels of proteins involved in protein metabolism, nucleic acid metabolism, angiogenesis, deregulation of cellular energetics and methylation processes, and decreased levels of proteins involved in apoptosis and immune response. These proteins are able to classify stage IIIc patients into prognostic subgroups (P < 0.02). This is the first report of potential prognostic markers from stage III melanoma using proteomic analyses. Validation of these protein markers in larger patient cohorts should define protein signatures that enable better stratification of stage III melanoma patients.

LGX818 is a new-generation BRAF inhibitor (BRAFi) that is currently undergoing phase 3 trials for the treatment of BRAF mutant metastatic melanoma patients (NCT01909453). Cutaneous toxicities associated with the administration of BRAF inhibitors are considered to be induced by the paradoxical activation of the mitogen-activated protein kinase pathway in wild-type BRAF cells. Changes in naevi, including new naevi, hyperpigmentation and fading of existing naevi, have also been reported. In addition, some patients receiving these therapies have developed second primary melanomas. As a consequence, the importance of sequential digital dermoscopy in all patients treated with a BRAFi to detect new primary melanomas has been emphasized. A 61-year-old man with BRAF mutant stage IV metastatic melanoma was commenced on the phase 1 trial of LGX818 at 300 mg daily in 2013. After 2 months of therapy, the patient was noted to have developed eruptive naevi, fading of existing naevi and darkening of other naevi. Excision of a new pigmented lesion from the back indicated a compound naevus. Immunohistochemistry showed that the naevus cells lacked a BRAF V600E mutation. This is the first reported case of eruptive naevi in a patient treated with LGX818. The absence of the BRAF V600E mutation within a changing naevus supports the theory that BRAFi stimulates the proliferation of wild-type BRAF cells. Close dermatological surveillance is important for all patients treated with any type of BRAFi.

Inositol polyphosphate 5-phosphatases can terminate downstream signalling of phosphatidylinositol-3 kinase; however, their biological role in the pathogenesis of cancer is controversial. Here we report that the inositol polyphosphate 5-phosphatase, phosphatidylinositol 4,5-bisphosphate 5-phosphatase, has a tumour suppressive role in melanoma. Although it is commonly downregulated in melanoma, overexpression of phosphatidylinositol 4,5-bisphosphate 5-phosphatase blocks Akt activation, inhibits proliferation and undermines survival of melanoma cells in vitro, and retards melanoma growth in a xenograft model. In contrast, knockdown of phosphatidylinositol 4,5-bisphosphate 5-phosphatase results in increased proliferation and anchorage-independent growth of melanocytes. Although DNA copy number loss is responsible for downregulation of phosphatidylinositol 4,5-bisphosphate 5-phosphatase in a proportion of melanomas, histone hypoacetylation mediated by histone deacetylases HDAC2 and HDAC3 through binding to the transcription factor Sp1 at the PIB5PA gene promoter appears to be another commonly involved mechanism. Collectively, these results establish the tumour suppressive role of phosphatidylinositol 4,5-bisphosphate 5-phosphatase and reveal mechanisms involved in its downregulation in melanoma.

Concern regarding the presence of intertumoral heterogeneity of BRAF mutation status in patients with metastatic melanoma has led to uncertainty surrounding which specimens should preferentially undergo BRAF testing. We sought to examine the extent of intrapatient heterogeneity of BRAF(V600E) protein expression in patients with multiple tumors. Sixty-four patients with 171 tumors at various stages of disease progression had tumor BRAF(V600E) protein expression immunohistochemically (IHC) assessed using the BRAF(V600E) mutant-specific antibody VE1. Melanoma sections were examined for staining intensity (score 0 to 3), the presence of intratumoral heterogeneity, and concordance with molecular BRAF genotype. Intrapatient, intertumoral heterogeneity of BRAF(V600E) expression was also assessed by comparing VE1 staining on different tumors within the same patient. All specimens from 64 patients displayed complete intertumoral homogeneity of BRAF(V600E) expression status, and all tumors had concordant molecular and IHC BRAF status. Only 1 patient demonstrated >1 level of staining intensity heterogeneity between specimens. Intratumoral heterogeneity of staining intensity was not observed in any specimen. IHC-measured BRAF(V600E) protein expression displays complete intertumoral homogeneity, minimal intertumoral intensity heterogeneity, and no intratumoral heterogeneity in metastatic melanoma patients in various stages of disease progression. Our results suggest that, provided there is adequate quantity of viable tumor cells and minimal admixture of nontumor cells, testing any melanoma sample from a patient with metastatic disease will accurately determine BRAF status for treatment planning.

Abstract Inositol polyphosphate 4-phosphatase type II (INPP4B) inhibits phosphatidylinositol 3-kinase (PI3K)/Akt signaling and is emerging as a tumor suppressor in a variety of tissues. Here we report that, conversely, it functions as an oncogenic regulator in human melanoma through activating PI3K/SGK3 signaling. While it was upregulated in a subset of melanomas, knockdown of INPP4B inhibited melanoma cell proliferation in vitro, and retarded melanoma growth in a xenograft model. In contrast, overexpression of INPP4B resulted in increased proliferation and anchorage-independent growth of melanocytes. Strikingly, INPP4B did not impinge on activation of Akt in melanocytic cells. Instead, it promoted PI3K/SGK3 signaling, in that INPP4B knockdown inhibited, whereas overexpression of INPP4B enhanced, activation of SGK3. Indeed, the effect of INPP4B on melanocytic cell proliferation was due to enhanced activation of SGK3, as co-introduction of an active form of SGK3 rescued melanocytes and melanoma cells from inhibition of proliferation triggered by INPP4B knockdown, and knockdown of SGK3 abolished enhancement in cell proliferation resulting from INPP4B overexpression. Upregulation of INPP4B appeared largely due to downregulation of microRNA-494 (miR-494) and/or miR-599 as a result of gene copy number reduction in melanoma cells. Collectively, these results reveal that INPP4B upregulation mediated by loss of miR-494 and/or miR-599 promotes melanoma cell proliferation through activation of PI3K/SGK3 signaling, and suggest that the role of INPP4B in the pathogenesis of cancers of different origins needs to be defined discretely. Citation Format: Chen Chen Jiang, Meng Na Chi, Su Tang Guo, James S. Wilmott, Xiang Yun Guo, Xu Guang Yan, Chun Yan Wang, Xiao Ying Liu, Lei Jin, Hsin-Yi Tseng, Amanda Croft, Hubert Hondermarck, Tao Liu, Richard A. Scolyer, Xu Dong Zhang. Inositol polyphosphate 4-phosphatase II activates PI3K/SGK3 signaling to promote proliferation of human melanoma cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4718. doi:10.1158/1538-7445.AM2015-4718

A minority of patients with thin melanomas had SLNB performed and the SLN positivity rate was low. This study did not confirm tumor ulceration, mitoses, or thickness as statistically significant predictors for SLN metastasis.

e20011 Background: Patients with positive sentinel lymph node biopsies (SLNB) that undergo a completion lymphadenectomy have variable five-year survival rates ranging from 39-70%. PD-1 and PD-L1 inhibitors have significantly improved recurrence free (RFS) and overall survival (OS) in AJCC stage IIIC/IV metastatic melanoma patients. The aims of this study were to characterise subpopulations of lymphocytes that interact with metastatic melanoma cells in SLNB, to determine tumoral PD-L1 expression and to identify whether the PD-1/PD-L1 pathway contributes to immune escape in these patients to provide a rationale for the use of anti-PD-1 inhibitors in the adjuvant setting and aid in the selection of patients for this treatment modality. Methods: The metastatic melanoma containing SLNB’s from sixty treatment-naive patients were analysed for CD3, CD4, CD8, FOXP3, PD-1, and PD-L1 and correlated clinico-pathologic features and outcome. Results: Tumoral PD-L1 expression ( ≥ 1%-cutoff) was present in 43.3% (n = 26) cases. Cox proportional hazard analysis showed a positive correlation between intratumoral CD3+ lymphocytes and RFS/OS (cutoff > 39.5,HR = 0.36(0.17-0.76),p = 0.005;HR = 0.29(0.14-0.61),p = 0.0005,respectively), a positive correlation between intratumoral CD4+ lymphocytes and RFS/OS (cutoff > 24,HR = 0.34(0.15-0.77),p = 0.007;HR = 0.32(0.14-0.74),p = 0.005,respectively) and a positive correlation between intratumoral CD8+ lymphocytes and RFS/OS (cutoff > 29,HR = 0.42(0.21-0.85),p = 0.013;HR = 0.32(0.19-0.78),p = 0.006respectively) in our cohort of patients. There was a negative correlation between peritumoral PD-1+ lymphocytes and RFS/OS (cutoff > 1.5,HR = 2.67(1.17-6.13),p = 0.016;HR = 2.74(1.14-6.76),p = 0.019respectively). Conclusions: Expression of PD-L1 in metastatic melanoma-positive SLNB’s provides a rationale for trials of anti-PD-1 therapy in AJCC stage IIIA melanoma patients, particularly those with peritumoral PD-1+ lymphocytes. The expression of immune markers may also be useful to predict the outcome of patients following a positive SNLB.