Familial Melanoma Patients Research Articles

Melanoma in children and adolescents: analysis of susceptibility genes in 123 Italian patients.

A polygenic inheritance involving high, medium and low penetrance genes has been suggested for melanoma susceptibility in adults, but genetic information is scarce for paediatric patients. We aim to analyse the major high and intermediate melanoma risk genes, CDKN2A, CDK4, POT1, MITF and MC1R, in a large multicentre cohort of Italian children and adolescents in order to explore the genetic context of paediatric melanoma and to reveal potential differences in heritability between children and adolescents. One-hundred-twenty-three patients (<21 years) from nine Italian centres were analysed for the CDKN2A, CDK4, POT1, MITF, and MC1R melanoma predisposing genes. The rate of gene variants was compared between sporadic, familial and multiple melanoma patients and between children and adolescents, and their association with clinico-pathological characteristics was evaluated. Most patients carried MC1R variants (67%), while CDKN2A pathogenic variants were found in 9% of the cases, the MITF E318K in 2% of patients and none carried CDK4 or the POT1 S270N pathogenic variant. Sporadic melanoma patients significantly differed from familial and multiple cases for the young age at diagnosis, infrequent red hair colour, low number of nevi, low frequency of CDKN2A pathogenic variants and of the MC1R R160W variant. Melanoma in children (≤12 years) had more frequently spitzoid histotype, were located on the head/neck and upper limbs and had higher Breslow thickness. The MC1R V92M variant was more common in children than in adolescents. CDKN2A common polymorphisms and MC1R variants were associated with a high number of nevi. Our results confirm the scarce involvement of the major high-risk susceptibility genes in paediatric melanoma and suggest the implication of MC1R gene variants especially in the children population.

DNA Repair and Immune Response Pathways Are Deregulated in Melanocyte-Keratinocyte Co-cultures Derived From the Healthy Skin of Familial Melanoma Patients.

Familial melanoma accounts for 10% of cases, being CDKN2A the main high-risk gene. However, the mechanisms underlying melanomagenesis in these cases remain poorly understood. Our aim was to analyze the transcriptome of melanocyte-keratinocyte co-cultures derived from healthy skin from familial melanoma patients vs. controls, to unveil pathways involved in melanoma development in at-risk individuals. Accordingly, primary melanocyte-keratinocyte co-cultures were established from the healthy skin biopsies of 16 unrelated familial melanoma patients (8 CDKN2A mutant, 8 CDKN2A wild-type) and 7 healthy controls. Whole transcriptome was captured using the SurePrint G3 Human Microarray. Transcriptome analyses included: differential gene expression, functional enrichment, and protein-protein interaction (PPI) networks. We identified a gene profile associated with familial melanoma independently of CDKN2A germline status. Functional enrichment analysis of this profile showed a downregulation of pathways related to DNA repair and immune response in familial melanoma (P < 0.05). In addition, the PPI network analysis revealed a network that consisted of double-stranded DNA repair genes (including BRCA1, BRCA2, BRIP1, and FANCA), immune response genes, and regulation of chromosome segregation. The hub gene was BRCA1. In conclusion, the constitutive deregulation of BRCA1 pathway genes and the immune response in healthy skin could be a mechanism related to melanoma risk.

Dermoscopy comparative approach for early diagnosis in familial melanoma: influence of MC1R genotype

MC1R polymorphisms interact with CDKN2A mutations modulating melanoma risk and contribute to a less suspicious clinical and dermoscopic appearance of melanomas. Different strategies, including dermoscopic comparative approach and digital monitoring, are used for the melanoma diagnosis in this context. To analyse the diagnostic accuracy of the morphologic approach and comparative approach in dermoscopy, and to detect melanoma in familial melanoma (FamMM) patients according to different genetic backgrounds. Two independent readers evaluated 415 lesions belonging to 25 FamMM: 26 melanomas (62% in situ, 36% early invasive) and 389 naevi, blinded for dermoscopic and histopathologic diagnosis, following two different steps. First step-Randomized: all lesions were randomly located in one single folder. Second step-Comparative approach: the lesions were clustered by patient. Sensitivity, specificity and number needed to excise (NNE) for melanoma diagnosis were calculated for both diagnostic strategies. Sensitivity and specificity were also assessed regarding the genetic background. The comparative approach showed lower sensitivity compared to the morphologic approach (69.2 and 73.1 vs. 76.9 both readers) but better specificity (95.9 and 95.1 vs. 84.3 and 90.2, respectively). NNE was better in the comparative approach. The readers had more difficulties diagnosing lesions from CDKN2A mutation carriers with red hair colour (RHC) MC1R variants. The comparative approach can be useful in high-risk patients to decrease the NNE. Early melanomas in CDKN2A carriers with RHC polymorphisms are more difficult to diagnose even with the comparative approach and benefit from the detection of changes during digital dermoscopy monitoring for early diagnosis.

Familial Melanoma: Diagnostic and Management Implications

BackgroundAn estimated 5%–10% of all cutaneous melanoma cases occur in families. This review describes susceptibility genes currently known to be involved in melanoma predisposition, genetic testing of familial melanoma patients, and management implications.ResultsCDKN2A is the major high-penetrance susceptibility gene with germline mutations identified in 20%–40% of melanoma families. A positive CDKN2A mutation status has been associated with a high number of affected family members, multiple primary melanomas, pancreatic cancer, and early age at melanoma onset. Mutations in the other melanoma predisposition genes—CDK4, BAP1, TERT, POT1, ACD, TERF2IP, and MITF—are rare, overall contributing to explain a further 10% of familial clustering of melanoma. The underlying genetic susceptibility remains indeed unexplained for half of melanoma families. Genetic testing for melanoma is currently recommended only for CDKN2A and CDK4, and, at this time, the role of multigene panel testing remains under debate. Individuals from melanoma families must receive genetic counseling to be informed about the inclusion criteria for genetic testing, the probability of an inconclusive result, the genetic risk for melanoma and other cancers, and the debatable role of medical management. They should be counseled focusing primarily on recommendations on appropriate lifestyle, encouraging skin self-examination, and regular dermatological screening.ConclusionsGenetic testing for high-penetrance melanoma susceptibility genes is recommended in melanoma families after selection of the appropriate candidates and adequate counseling of the patient. All patients and relatives from melanoma kindreds, irrespective of their mutation status, should be encouraged to adhere to a correct ultraviolet exposure, skin self-examination, and surveillance by physicians.

CDKN2A/CDK4 Status in Greek Patients with Familial Melanoma and Association with Clinico-epidemiological Parameters.

Approximately 5–10% of melanoma cases occur in a familial context. CDKN2A/CDK4 were the first high- penetrance melanoma genes identified. The aims of this study were to evaluate CDKN2A/CDK4 variants in Greek familial melanoma patients and to correlate the mutational status with specific clinico-epidemiological characteristics. A cross-sectional study was conducted by genotyping CDKN2A/CDK4 variants and selected MC1R polymorphisms in 52 melanoma-prone families. Descriptive statistics were calculated and comparisons were made using the X2 test, Fisher’s exact test and Student’s t-test for statistical analysis, as appropriate. CDKN2A variants were detected in 46.2% of melanoma-prone families, while a CDK4 variant was found in only one family. This study confirmed that, in the Greek population, the age at melanoma diagnosis was lower in patients carrying a variant in CDKN2A compared with wild-type patients. No statistically significant associations were found between CDKN2A mutational status and MC1R polymorphisms.

Characterization of melanoma susceptibility genes in high-risk patients from Central Italy

Genetic susceptibility to cutaneous melanoma has been investigated in Italian high-risk melanoma patients from different geographical regions. CDKN2A, CDK4, and MC1R genes have been screened in most studies, MITF and POT1 were screened in only one study, and none analyzed the TERT promoter. We carried out a mutational analysis of CDKN2A, CDK4 exon 2, POT1 p.S270N, MITF exon 10, MC1R, and the TERT promoter in 106 high-risk patients with familial melanoma (FM) and sporadic multiple primary melanoma (spMPM) from Central Italy and evaluated mutations according to the clinicopathological characteristics of patients and lesions. In FM, CDKN2A mutations were detected in 8.3% of the families, including one undescribed exon 1β mutation (p.T31M), and their prevalence increased with the number of affected relatives within the family. MC1R variants were identified in 65% of the patients and the TERT rs2853669 promoter polymorphism was identified in 58% of the patients. A novel synonymous mutation detected in MITF exon 10 (c.861A>G, p.E287E), although predicted as a splice site mutation by computational tools, could not functionally be confirmed to alter splicing. For spMPM, 3% carried CDKN2A mutations, 79% carried MC1R variants, and 47% carried the TERT rs2853669 promoter polymorphism. MC1R variants were associated with fair skin type and light hair color both in FM and in spMPM, and with a reduction of age at diagnosis in FM patients. Mutations in CDK4 exon 2 and the POT1 p.S270N mutation were not detected. A low frequency of CDKN2A mutations and a high prevalence of MC1R variants characterize high-risk melanoma patients from Central Italy.

Detection of Exosomal miRNAs in the Plasma of Melanoma Patients

MicroRNAs (miRNAs) are a class of 22–25 nucleotide RNAs that control gene expression at the post-transcriptional level. MiRNAs have potential as cancer biomarkers. Melanoma is a highly aggressive form of skin cancer accounting for almost 4% of cancers among men and women, and ~80% of skin cancer-related deaths in the US. In the present study we analyzed plasma-derived exosomal miRNAs from clinically affected and unaffected familial melanoma patients (CDKN2A/p16 gene carriers) and compared them with affected (nonfamilial melanoma) and unaffected control subjects in order to identify novel risk biomarkers for melanoma. Intact miRNAs can be isolated from the circulation because of their presence in exosomes. A number of differentially regulated miRNAs identified by NanoString human V2 miRNA array were validated by quantitative PCR. Significantly, miR-17, miR-19a, miR-21, miR-126, and miR-149 were expressed at higher levels in patients with metastatic sporadic melanoma as compared with familial melanoma patients or unaffected control subjects. Surprisingly, no substantial differences in miRNA expression were detected between familial melanoma patients (all inclusive) and unaffected control subjects. The miRNAs differentially expressed in the different patient cohorts, especially in patients with metastatic melanoma, may play important roles in tumor progression and metastasis, and may be used as predictive biomarkers to monitor remission as well as relapse following therapeutic intervention.

Uveal melanoma and renal cell carcinoma both metastatic to the liver

PurposeGermline mutations in the BRCA1‐associated protein‐1 gene (BAP1) predispose carriers to several types of cancer, including uveal and cutaneous melanoma, mesothelioma, renal cell cancer, and possibly other diverse tumor types. Approximately 2% of consecutive Finnish uveal melanoma patients harbor a germline mutation in BAP1.MethodsCase report.ResultsA 53‐year‐old man was diagnosed with renal cancer in 2006. No metastasis was detected during a 5‐year follow‐up after surgery. In 2011, he noted decreased vision in his left eye. Ophthalmological examination revealed a suspicious choroidal mass and the patient was referred to the ocular Oncology service, Helsinki University Eye Clinic. A choroidal melanoma with a largest basal dimension of 15.5 mm and thickness of 11.1 mm and no metastases was detected (T3aN0M0, stage IIB). He received brachytherapy with an iodine plaque. Three years later he had liver metastases, and biopsies indicated the presence of both uveal melanoma and renal carcinoma metastases. Further, a sister of his father also has had uveal melanoma. Given that the patient was a candidate to harbor a germline BAP1 mutation we sequenced the gene. No mutation was found in the coding regions or adjacent intronic sequences. Further, we carried out whole exome sequencing, and no mutations or mosaicism were found in BAP1, BRCA1, SF3B1, or EIF1AX.ConclusionsNot all familial uveal melanoma patients even with history of renal cell cancer harbor an obvious BAP1 germline mutation. Currently, we are analyzing histological samples to further investigate the possible role of BAP1 in tumor tissue and genetic data to find or exclude indirect effect on BAP1 function.

Frequency and characteristics of familial melanoma in Spain: the FAM-GEM-1 Study.

IntroductionFamilial history of melanoma is a well-known risk factor for the disease, and 7% melanoma patients were reported to have a family history of melanoma. Data relating to the frequency and clinical and pathological characteristics of both familial and non-familial melanoma in Spain have been published, but these only include patients from specific areas of Spain and do not represent the data for the whole of Spain.Patients and methodsAn observational study conducted by the Spanish Group of Melanoma (GEM) analyzed the family history of patients diagnosed with melanoma between 2011 and 2013 in the dermatology and oncology departments.ResultsIn all, 1047 patients were analyzed, and 69 (6.6%) fulfilled criteria for classical familial melanoma (two or more first-degree relatives diagnosed with melanoma). Taking into account other risk factors for familial melanoma, such as multiple melanoma, pancreatic cancer in the family or second-degree relatives with melanoma, the number of patients fulfilling the criteria increased to 165 (15.8%). Using a univariate analysis, we determined that a Breslow index of less than 1 mm, negative mitosis, multiple melanoma, and a history of sunburns in childhood were more frequent in familial melanoma patients, but a multivariate analysis revealed no differences in any pathological or clinical factor between the two groups.ConclusionsSimilar to that observed in other countries, familial melanoma accounts for 6.6% of melanoma diagnoses in Spain. Although no differences in the multivariate analysis were found, some better prognosis factors, such as Breslow index, seem more frequent in familial melanoma, which reflect a better early detection marker and/or a different biological behavior.

Analysis of Latvian familial melanoma patients shows novel variants in the noncoding regions of CDKN2A and that the CDK4 mutation R24H is a founder mutation

Hereditary cutaneous melanoma is associated with mutations in the high-risk CDKN2A gene in about 40% of melanoma-prone families. Mutations in the CDK4 gene are the cause in only a few pedigrees. In this study, we analyzed 20 Latvian familial melanoma probands and carried out a comprehensive analysis of CDKN2A including sequencing of its promoter/intronic regions and deletion screening. We also analyzed the critical second exon of the CDK4 gene. One novel intronic variant (IVS2+82C>T) of the CDKN2A gene and a small deletion (c.-20677_-20682delGTACGC) in its promoter region were found. Genotyping of the novel variants in larger melanoma and control groups indicated that the deletion increases the risk of melanoma (odds ratio=6.353, 95% confidence interval: 1.34-30.22, P=0.0168). The CDK4 gene analysis showed a Latvian melanoma family with the mutation R24H carried on the same haplotype as in two previously described Latvian CDK4-positive families. Our study suggests that the main risk gene in Latvian families with a strong family history of melanoma is CDK4 and that most of the other cases analyzed could be sporadic or associated with low-penetrance risk genes.

Impact of Dermoscopy on the Management of High-risk Patients From Melanoma Families: A Prospective Study

Few studies have investigated the impact of dermoscopy on the management of relatives from melanoma families. The objective of this study was to assess the impact of dermoscopy on clinical diagnosis and management decisions in high-risk familial melanoma patients. In a prospective study 132 consecutive patients were recruited from the pigmented lesions clinic of a tertiary reference centre for familial melanoma. Dermatologists expert in dermoscopy identified 49 suspicious pigmented lesions and recorded pre- and post-dermoscopy diagnoses and management decisions. Dermoscopy was performed in 37% of the patients. Two melanomas were identified. Dermoscopy did not influence sensitivity (1.0), but resulted in 42% fewer excisions, increasing specificity from 0.53 to 0.74 (p = 0.031). Dermoscopy resulted in a large reduction in the number of unnecessary excisions. These results suggest that the main effect of dermoscopy in clinical practice for this high risk population is a significant increase in specificity, rather than sensitivity.

Management of Melanoma Families

In this review we have aimed to focus on the clinical management of familial melanoma patients and their relatives. Along this line three major topics will be discussed: (1) management/screening of familial melanoma families: what is advised and what is the evidence thereof; (2) variability of families worldwide with regard to clinical phenotype, including cancer spectrum and likelihood of finding germline mutations and (3) background information for clinicians on the molecular biology of familial melanoma and recent developments in this field.

MC1R variation and melanoma risk in the Swedish population in relation to clinical and pathological parameters

The genetic background of cutaneous malignant melanoma (CMM) includes both germ line aberrations in high-penetrance genes, like CDKN2A, and allelic variation in low-penetrance genes like the melanocortin-1 receptor gene, MC1R. Red-hair colour associated MC1R alleles (RHC) have been associated with red hair, fair skin and risk of CMM. We investigated MC1R and CDKN2A variation in relation to phenotype, clinical factors and CMM risk in the Swedish population. The study cohort consisted of sporadic primary melanoma patients, familial melanoma patients and a control group. An allele-dose dependent increase in melanoma risk for carriers of variant MC1R alleles (after adjusting for phenotype), with an elevated risk among familial CMM patients, was observed. This elevated risk was found to be significantly associated with an increased frequency of dysplastic nevi (DN) among familial patients compared to sporadic patients. MC1R variation was found to be less frequent among acral lentiginous melanomas (ALM) and dependent on tumour localisation. No association was found between CDKN2A gene variants and general melanoma risk. Two new variants in the POMC gene were identified in red haired individuals without RHC alleles.

The limited specificity of histological examination in the diagnosis of dysplastic nevi

Dysplastic nevi were originally described as a distinct entity with specific clinical and histological features of importance as direct precursors of malignant melanoma and as markers of patients at increased risk of developing melanoma in the setting of familial melanoma. Nevi with the clinical and histological features described first as 'B-K moles' and later as 'dysplastic nevi' clearly do exist and do sometimes represent melanoma precursors or melanoma risk markers, but it is now recognized that most dysplastic nevi never progress to melanoma, that the histological features originally described in nevi in familial melanoma patients are poorly correlated with dysplastic nevi as they are defined clinically, and that overlapping or identical histological features are found in a variety of other melanocytic lesions including small (< 5 mm) melanocytic nevi, lentiginous nevi, atypical (dysplastic) lentiginous nevi, lentiginous melanoma, lentigo maligna and nevi in an ever-growing number of 'special sites'. This article will briefly review the evolution of our understanding of the histological range of nevi and the histological differential diagnosis of dysplastic nevi.

Prevalence of variations in melanoma susceptibility genes among Slovenian melanoma families

BackgroundTwo high-risk genes have been implicated in the development of CM (cutaneous melanoma). Germline mutations of the CDKN2A gene are found in < 25% of melanoma-prone families and there are only seven families with mutation of the CDK4 gene reported to date. Beside those high penetrance genes, certain allelic variants of the MC1R gene modify the risk of developing the disease.The aims of our study were: to determine the prevalence of germline CDKN2A mutations and variants in members of families with familial CM and in patients with multiple primary CM; to search for possible CDK4 mutations, and to determine the frequency of variations in the MC1R gene.MethodsFrom January 2001 until January 2007, 64 individuals were included in the study. The group included 28 patients and 7 healthy relatives belonging to 25 families, 26 patients with multiple primary tumors and 3 children with CM. Additionally 54 healthy individuals were included as a control group. Mutations and variants of the melanoma susceptibility genes were identified by direct sequencing.ResultsSeven families with CDKN2A mutations were discovered (7/25 or 28.0%). The L94Q mutation found in one family had not been previously reported in other populations. The D84N variant, with possible biological impact, was discovered in the case of patient without family history but with multiple primary CM. Only one mutation carrier was found in the control group. Further analysis revealed that c.540C>T heterozygous carriers were more common in the group of CM patients and their healthy relatives (11/64 vs. 2/54). One p14ARF variant was discovered in the control group and no mutations of the CDK4 gene were found.Most frequently found variants of the MC1R gene were T314T, V60L, V92M, R151C, R160W and R163Q with frequencies slightly higher in the group of patients and their relatives than in the group of controls, but the difference was statistically insignificant.ConclusionThe present study has shown high prevalence of p16INK4A mutations in Slovenian population of familial melanoma patients (37%) and an absence of p14ARF or CDK4 mutations.

Comparison between familial and sporadic cutaneous melanoma in Valencia, Spain

Some clinical, pathological and genetic features have been associated to familial melanoma, particularly multiple melanoma and earlier age at diagnosis. To compare the clinical, epidemiological and pathological differences between familial and sporadic melanoma patients in Valencia, Spain, a series of 959 patients with cutaneous melanoma were selected at a single institution. For this study the following variables were selected: age, sex, melanoma site and presence of solar lentigines on the melanoma surrounding skin, histological subtype, tumor thickness, stage, family and personal history of cutaneous melanoma and of other neoplasias, personal history of non-melanoma skin cancer, past personal history of severe sunburns, cutaneous phenotype (phototype, hair and eyes colors number of common nevus, number of atypical nevi, presence of solar lentigines). Forty-one (4.28%) familial and 918 sporadic melanoma were identified. Among the multiple variables studied, a younger age at diagnosis (median age of 42 vs 53 years), higher frequency of the presence of at least one clinically atypical nevus (36.1% vs 17.7%), multiple melanomas (12.2% vs 3.4%) and red/blonde hair (33.3% vs 18.9%), and a lower rate of cases with solar lentigines in melanoma site (33.3% vs 56.3%) were found for familial cases. Except for hair color and age, the other variables remained statistically significant after the multivariate study. Interestingly, no acral melanomas were found among the familial cases. In summary, phenotypic risk factors for familial melanoma are a tendency to develop multiple melanomas, to have clinically atypical nevi and to present less actinic damage at the melanoma site. All these results enhance the relevancy of genetic susceptibility associated to the ability to produce atypical nevi and partly to a higher sensitivity to the sun.

Population-Based Analysis of Prognostic Factors and Survival in Familial Melanoma

Familial melanoma patients are reported to present with thinner melanomas, to be younger at the time of diagnosis, and to have a greater likelihood of developing multiple primary tumors. We sought to determine whether melanomas that occur in a familial setting demonstrate different prognostic and survival statistics relative to sporadic melanoma. This population-based study used the Utah Cancer Registry and Utah Population Database to objectively evaluate prognostic and survival statistics of the familial melanoma population. From 1973 to 1999, there were 7,785 cases of invasive melanoma identified through the Utah Cancer Registry. These were linked to the Utah Population Database, resulting in 2,659 subjects with family-history information from which a familiality score could be calculated. Cases scored in the top ninth percentile were assigned as high familial risk, and the remaining 91% were considered low familial risk. Multivariate logistic-regression analysis found no association between sex, Breslow depth, Clark level, or survival and the familial status. Age at first diagnosis of invasive melanoma was slightly lower in the high-familial-risk group (57 v 60 years; P = .03). High-familial-risk subjects had more melanomas diagnosed at age 30 or younger (12% v 6%; P < .001). A significant difference in the overall number of individuals with two or more primary malignant melanomas was not detected among the groups (P = .2). These data suggest that melanomas occurring in the context of an underlying inherited susceptibility do not have a significantly different biologic behavior.

MELPREDICT: a logistic regression model to estimate CDKN2A carrier probability

Background: Heritable alterations in CDKN2A account for a subset of familial melanoma cases although no robust method exists to identify those at risk of being a mutation carrier. Methods: We...

Ectopic expression of tyrosinase increases melanin synthesis and cell death following UVB irradiation in fibroblasts from familial atypical multiple mole and melanoma (FAMMM) patients.

Patients with familial atypical multiple mole and melanoma (FAMMM) [so-called familial dysplastic naevus syndrome (FDNS)] have a high risk for the development of malignant melanoma. The underlying gene defect has an autosomal dominant inheritance with variable expression and incomplete penetrance. Fibroblasts derived from FAMMM patients have high sensitivity to UVC and mutagens, e.g. 4-nitroquinoline-1-oxide. We were interested in identifying how the combination of inherent sensitivity to UV light and abnormal melanin synthesis interacts in the development of melanoma in FAMMM patients. Intermediates of melanin synthesis produce free radicals that are toxic to cells. Atypical moles (dysplastic naevi) are engaged in the biosynthesis of abnormal melanin pigments. This study examined whether there was any abnormal melanin pigmentation or cell damage after the ectopic expression of tyrosinase in fibroblasts from FAMMM patients when compared with fibroblasts from normal subjects. Fibroblasts from FAMMM patients (3012T and 3072T) were associated with a higher sensitivity than normal human fibroblasts to the toxicity of UVB. When cells were infected with tyrosinase-expressing adenovirus (Ad-HT) and irradiated with UVB, FAMMM fibroblasts showed higher tyrosinase activity, produced more melanin pigments and were degraded more significantly than normal human fibroblasts. Western blot analysis revealed that Ad-HT-infected 3072T produced a larger amount of tyrosinase protein than did Ad-HT-infected normal fibroblasts after UVB irradiation. Our findings suggest: (1) that FAMMM fibroblasts have an unknown machinery which enhances tyrosinase expression by UVB irradiation; and (2) that the resulting increase in melanin synthesis affects the cytotoxicity of UVB to FAMMM fibroblasts. All of these processes may be involved in the genomic instability and development of melanoma in FAMMM patients.

Expression and mislocalization of mutant p16 proteins in melanocytic lesions from familial melanoma patients

Several studies have investigated loss of p16 protein expression in sporadic melanocytic lesions and found that it correlates with advanced stages of melanoma progression. Whether p16 inactivation occurs only late in progression or is also associated with early stages is still debated. Little is known about the correlation between loss of p16 expression and tumor progression in familial melanoma as no systematic study has been conducted on p16 expression in melanocytic tumors from patients carrying germline CDKN2A mutations. The presence of germline mutations may indicate that p16 inactivation could be involved in initiation and early development of melanoma. We analyzed 98 early primary lesions from familial patients, previously tested for germline CDKN2A status, by quantitative and qualitative immunohistochemistry using three p16 antibodies. p16 expression was inversely correlated with tumor progression and was significantly lower in melanomas, including in situ lesions, than in nevi. Of other features analysed, tumor thickness showed the most significant correlation to p16 levels. Lesions from mutation-negative patients displayed combined nuclear and cytoplasmic staining. However, several mutation-positive lesions (G101W, 113insR, M53I, R24P, 33ins24), including benign nevi, showed nuclear mislocalization, confirming in vivo previous in vitro immunofluorescence studies that suggested that subcellular distribution is indicative of functional impairment of p16, regardless of CDK4 and CDK6 binding activity. Functional characterization of different p16 interacting proteins and their localization could better explain the different behaviour in subcellular localization of mutated p16.