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Cancers, including cutaneous melanoma, can cluster in families. In addition to environmental etiological factors such as ultraviolet radiation, cutaneous melanoma has a strong genetic component. Genetic risks for cutaneous melanoma range from rare, high-penetrance mutations to common, low-penetrance variants. Known high-penetrance mutations account for only about half of all densely affected cutaneous melanoma families, and the causes of familial clustering in the remainder are unknown. We hypothesize that some clustering is due to the cumulative effect of a large number of variants of individually small effect. Common, low-penetrance genetic risk variants can be combined into polygenic risk scores. We used a polygenic risk score for cutaneous melanoma to compare families without known high-penetrance mutations with unrelated melanoma cases and melanoma-free controls. Family members had significantly higher mean polygenic load for cutaneous melanoma than unrelated cases or melanoma-free healthy controls (Bonferroni-corrected t-test P = 1.5 × 10−5 and 6.3 × 10−45, respectively). Whole genome sequencing of germline DNA from 51 members of 21 families with low polygenic risk for melanoma identified a CDKN2A p.G101W mutation in a single family but no other candidate high-penetrance melanoma susceptibility genes. This work provides further evidence that melanoma, like many other common complex disorders, can arise from the joint action of multiple predisposing factors, including rare high-penetrance mutations, as well as via a combination of large numbers of alleles of small effect.

Germline mutations of BRCA1 and BRCA2 predispose individuals to a high risk of breast and ovarian cancer, and elevated risk of other cancers, including those of the pancreas and prostate. BRCA2 mutation carriers may have increased risk of uveal melanoma (UM) and cutaneous melanoma (CM), but associations with these cancers in BRCA1 mutation carriers have been mixed. Here, we further assessed whether UM and CM are associated with BRCA1 or BRCA2 by assessing the presence, segregation and reported/predicted pathogenicity of rare germline mutations (variant allele frequency < 0.01) in families with multiple members affected by these cancers. Whole-genome or exome sequencing was performed on 160 CM and/or UM families from Australia, the Netherlands, Denmark and Sweden. Between one and five cases were sequenced from each family, totalling 307 individuals. Sanger sequencing was performed to validate BRCA1 and BRCA2 germline variants and to assess carrier status in other available family members. A nonsense and a frameshift mutation were identified in BRCA1, both resulting in premature truncation of the protein (the first at p.Q516 and the second at codon 91, after the introduction of seven amino acids due to a frameshift deletion). These variants co-segregated with CM in individuals who consented for testing and were present in individuals with pancreatic, prostate and breast cancer in the respective families. In addition, 33 rare missense mutations (variant allele frequency ranging from 0.00782 to 0.000001 in the aggregated ExAC data) were identified in 34 families. Examining the previously reported evidence of functional consequence of these variants revealed all had been classified as either benign or of unknown consequence. Seeking further evidence of an association between BRCA1 variants and melanoma, we examined two whole-genome/exome sequenced collections of sporadic CM patients (total N = 763). We identified one individual with a deleterious BRCA1 variant, however, this allele was lost (with the wild-type allele remaining) in the corresponding CM, indicating that defective BRCA1 was not a driver of tumorigenesis in this instance. Although this is the first time that deleterious BRCA1 mutations have been described in high-density CM families, we conclude that there is an insufficient burden of evidence to state that the increased familial CM or UM susceptibility is because of these variants. In addition, in conjunction with other studies, we conclude that the previously described association between BRCA2 mutations and UM susceptibility represents a rare source of increased risk.

Approximately 1-2% of cutaneous melanoma (CM) is classified as strongly familial. We sought to investigate unexplained CM predisposition in families negative for the known susceptibility genes using next generation sequencing of affected individuals. Segregation of germline variants of interest within families was assessed by Sanger sequencing. Several heterozygous variants in oculocutaneous albinism (OCA) genes: TYR, OCA2, TYRP1 and SLC45A2, were present in our CM cohort. OCA is a group of autosomal recessive genetic disorders, resulting in pigmentation defects of the eyes, hair and skin. Missense variants classified as pathogenic for OCA were present in multiple families and some fully segregated with CM. The functionally compromised TYR p.T373K variant was present in three unrelated families. In OCA2, known pathogenic variants: p.V443I and p.N489D, were present in three families and one family, respectively. We identified a likely pathogenic SLC45A2 frameshift variant that fully segregated with CM in a family of four cases. Another four-case family harboured cosegregating variants (p.A24T and p.R153C) of uncertain functional significance in TYRP1. We conclude that rare, heterozygous variants in OCA genes confer moderate risk for CM. This article is protected by copyright. All rights reserved.

BACKGROUND: The BRCA1-associated protein-1 (BAP1) tumor predisposition syndrome (BAP1-TPDS) is a hereditary tumor syndrome caused by germline pathogenic variants in BAP1 encoding a tumor suppressor associated with uveal melanoma, mesothelioma, cutaneous melanoma, renal cell carcinoma, and cutaneous BAP1-inactivated melanocytic tumors. However, the full spectrum of tumors associated with the syndrome is yet to be determined. Improved understanding of the BAP1-TPDS is crucial for appropriate clinical management of BAP1 germline variant carriers and their families, including genetic counseling and surveillance for new tumors. METHODS: We collated germline variant status, tumor diagnoses, and information on BAP1 immunohistochemistry or loss of somatic heterozygosity on 106 published and 75 unpublished BAP1 germline variant-positive families worldwide to better characterize the genotypes and phenotypes associated with the BAP1-TPDS. Tumor spectrum and ages of onset were compared between missense and null variants. All statistical tests were two-sided. RESULTS: The 181 families carried 140 unique BAP1 germline variants. The collated data confirmed the core tumor spectrum associated with the BAP1-TPDS and showed that some families carrying missense variants can exhibit this phenotype. A variety of noncore BAP1-TPDS -associated tumors were found in families of variant carriers. Median ages of onset of core tumor types were lower in null than missense variant carriers for all tumors combined (P

There is currently no effective treatment for metastasised uveal melanoma (UM). Recently, it was reported that a UM patient was responsive to checkpoint inhibitor (CI) treatment, due to a high tumour mutation burden correlated with a germline loss-of-function MBD4 mutation. Here, we report on another UM patient who carried an MBD4 germline nonsense variant (p.Leu563Ter) and her tumour showed a fivefold higher than average mutation burden. We confirmed the association between germline loss-of-function variant in MBD4 and CI response. The patient experienced stable disease (10 months) and survived 2 years with metastatic disease, which is twice as long as median survival. Additionally, the frequency of MBD4 loss-of-function variants in reported UM cohorts was 20 times higher than in an aggregated population genome database (P 5 × 10

The overall 5-year survival for melanoma is 91%. However, if distant metastasis occurs (stage IV), cure rates are, Highlights • A seven-miRNA panel (MELmiR-7) detected the presence of melanoma with high sensitivity (93%) and specificity (≥ 82%). • In serially collected stage IV specimens, members of the ‘MELmiR-7’ panel confirmed tumour progression in 100% of cases. • The ‘MELmiR-7’ panel is superior to currently used serological markers for melanoma progression, recurrence, and survival.

Mutations in Cyclin-Dependent Kinase Inhibitor 2A (CDKN2A) and Cyclin-Dependent Kinase 4 (CDK4) contribute to susceptibility in approximately 40% of high-density cutaneous melanoma (CMM) families and about 2% of unselected CMM cases. BRCA-1 associated protein-1 (BAP1) has been more recently shown to predispose to CMM and uveal melanoma (UMM) in some families; however, its contribution to CMM development in the general population is unreported. We sought to determine the contribution of these genes to CMM susceptibility in a population-based sample of cases from Australia. We genotyped 1,109 probands from Queensland families and found that approximately 1.31% harbored mutations in CDKN2A, including some with novel missense mutations (p.R22W, p.G35R and p.I49F). BAP1 missense variants occurred in 0.63% of cases but no CDK4 variants were observed in the sample. This is the first estimate of the contribution of BAP1 and CDK4 to a population-based sample of CMM and supports the previously reported estimate of CDKN2A germline mutation prevalence.

Germline mutations in the exonuclease domain of POLE have been shown to predispose to colorectal cancers and adenomas. POLE is an enzyme involved in DNA repair and chromosomal DNA replication. In order to assess whether such mutations might also predispose to cutaneous melanoma, we interrogated whole-genome and exome data from probands of 34 melanoma families lacking pathogenic mutations in known high penetrance melanoma susceptibility genes: CDKN2A, CDK4, BAP1, TERT, POT1, ACD and TERF2IP. We found a novel germline mutation, POLE p.(Trp347Cys), in a 7-case cutaneous melanoma family. Functional assays in S. pombe showed that this mutation led to an increased DNA mutation rate comparable to that seen with a Pol e mutant with no exonuclease activity. We then performed targeted sequencing of POLE in 1243 cutaneous melanoma cases and found that a further ten probands had novel or rare variants in the exonuclease domain of POLE. Although this frequency is not significantly higher than that in unselected Caucasian controls, we observed multiple cancer types in the melanoma families, suggesting that some germline POLE mutations may predispose to a broad spectrum of cancers, including melanoma. In addition, we found the first mutation outside the exonuclease domain, p.(Gln520Arg), in a family with an extensive history of colorectal cancer.

The shelterin complex protects chromosomal ends by regulating how the telomerase complex interacts with telomeres. Following the recent finding in familial melanoma of inactivating germline mutations in POT1, encoding a member of the shelterin complex, we searched for mutations in the other five components of the shelterin complex in melanoma families.Next-generation sequencing techniques were used to screen 510 melanoma families (with unknown genetic etiology) and control cohorts for mutations in shelterin complex encoding genes: ACD, TERF2IP, TERF1, TERF2, and TINF 2. Maximum likelihood and LOD [logarithm (base 10) of odds] analyses were used. Mutation clustering was assessed with χ(2) and Fisher's exact tests. P values under .05 were considered statistically significant (one-tailed with Yates' correction).Six families had mutations in ACD and four families carried TERF2IP variants, which included nonsense mutations in both genes (p.Q320X and p.R364X, respectively) and point mutations that cosegregated with melanoma. Of five distinct mutations in ACD, four clustered in the POT1 binding domain, including p.Q320X. This clustering of novel mutations in the POT1 binding domain of ACD was statistically higher (P = .005) in melanoma probands compared with population control individuals (n = 6785), as were all novel and rare variants in both ACD (P = .040) and TERF2IP (P = .022). Families carrying ACD and TERF2IP mutations were also enriched with other cancer types, suggesting that these variants also predispose to a broader spectrum of cancers than just melanoma. Novel mutations were also observed in TERF1, TERF2, and TINF2, but these were not convincingly associated with melanoma.Our findings add to the growing support for telomere dysregulation as a key process associated with melanoma susceptibility.

A substantial number of melanoma patients will develop multiple primary melanomas (MPM). Currently, little is known about the impact of MPM on survival.We aimed to determine whether melanoma survival is worse for patients with MPM compared to those with a single invasive primary melanoma (SPM).A cohort study was conducted. Patients were sourced from an Australian population, with follow-up information collected retrospectively from registry data. Melanoma-specific survival analysis was performed to find associated variables after adjustment for known prognostic factors, using four different models, each selecting a different index melanoma lesion.1068 stage I and II melanoma patients were followed up for a median of 24.4 years. MPM was found in 17.8% of the cohort (190 patients), more likely among males and older age groups. Other clinicopathological parameters were similar between the MPM and SPM (878 patients) cohorts. After adjustment for age, sex and Breslow thickness, MPM was a hazard for death from melanoma, across all models, reaching significance when considering the last invasive lesion as the index melanoma (HR = 2.76, P = 0.017).Patients with multiple invasive lesions seem more at risk of death from melanoma, independent of known prognostic factors.

Background CDKN2A and CDK4 are high risk susceptibility genes for cutaneous malignant melanoma. Melanoma families with CDKN2A germline mutations have been extensively characterised, whereas CDK4 families are rare and lack a systematic investigation of their phenotype. Methods All known families with CDK4 germline mutations (n=17) were recruited for the study by contacting the authors of published papers or by requests via the Melanoma Genetics Consortium (GenoMEL). Phenotypic data related to primary melanoma and pigmentation characteristics were collected. The CDK4 exon 2 and the complete coding region of the MC1R gene were sequenced. Results Eleven families carried the CDK4 R24H mutation whereas six families had the R24C mutation. The total number of subjects with verified melanoma was 103, with a median age at first melanoma diagnosis of 39 years. Forty-three (41.7%) subjects had developed multiple primary melanomas (MPM). A CDK4 mutation was found in 89 (including 62 melanoma cases) of 209 tested subjects. CDK4 positive family members (both melanoma cases and unaffected subjects) were more likely to have clinically atypical nevi than CDK4 negative family members (p

A gene for familial melanoma (MLM) has been mapped to 9p22-p13 by linkage analysis using simple tandem repeat polymorphisms (STRPs) at the IFNA and D9S126 loci. This localization is consistent with the finding of homozygous deletions of these markers in DNA from two melanoma cell lines, which suggest that the locus has the properties of a tumour suppressor gene. In an attempt to further define the position of the MLM locus we have typed 10 STRPs from the short arm of chromosome 9 in 15 Australian melanoma kindreds. Extended haplotype analysis of these markers and identification of recombinants in our pedigrees indicate that the MLM gene is flanked on the centromeric side by D9S169 and on the telomeric side by D9S156. These results limit the location of the MLM locus to an interval of about 16 centimorgans.

So far, two genes associated with familial melanoma have been identified, accounting for a minority of genetic risk in families. Mutations in CDKN2A account for approximately 40% of familial cases, and predisposing mutations in CDK4 have been reported in a very small number of melanoma kindreds. Here we report the whole-genome sequencing of probands from several melanoma families, which we performed in order to identify other genes associated with familial melanoma. We identify one individual carrying a novel germline variant (coding DNA sequence c.G1075A; protein sequence p.E318K; rs149617956) in the melanoma-lineage-specific oncogene microphthalmia-associated transcription factor (MITF). Although the variant co-segregated with melanoma in some but not all cases in the family, linkage analysis of 31 families subsequently identified to carry the variant generated a log of odds (lod) score of 2.7 under a dominant model, indicating E318K as a possible intermediate risk variant. Consistent with this, the E318K variant was significantly associated with melanoma in a large Australian case-control sample. Likewise, it was similarly associated in an independent case-control sample from the United Kingdom. In the Australian sample, the variant allele was significantly over-represented in cases with a family history of melanoma, multiple primary melanomas, or both. The variant allele was also associated with increased naevus count and non-blue eye colour. Functional analysis of E318K showed that MITF encoded by the variant allele had impaired sumoylation and differentially regulated several MITF targets. These data indicate that MITF is a melanoma-predisposition gene and highlight the utility of whole-genome sequencing to identify novel rare variants associated with disease susceptibility.

Cutaneous melanoma continues to increase in incidence in many countries, and intentional tanning is a risk factor for melanoma. The aim of this study was to understand how melanoma risk factors, perceived threat and preferences for a suntan relate to intentional tanning. Self-report data were collected on behalf of GenoMEL (www.genomel.org) from the general population using an online survey. A total of 8178 individuals completed the survey, with 72.8% of respondents being from Europe, 12.1% from Australia, 7.1% from the US, 2.5% from Israel and 5.5% from other countries. Seven percent of respondents had previously been diagnosed with melanoma and 8% had at least one first-degree relative with a previous melanoma. Overall, 70% reported some degree of intentional tanning during the past year, and 38% of respondents previously diagnosed with melanoma had intentionally tanned. The total number of risk factors was positively correlated with perceived risk of melanoma [correlation coefficient (rho) = 0.27], and negatively correlated with intentional tanning (rho = -0.16). Preference for a dark suntan was the strongest predictor of intentional tanning [regression coefficient (beta)= 0.35, P

To the Editor Germline aberrations in the CDKN2A gene are observed in some melanoma-prone families and represent high penetrance mutations (Hussussian et al., 1994; Kamb et al., 1994). INK4A (p16) and ARF (p14) are two distinct proteins encoded by the CDKN2A locus. Loss of INK4A has been associated with unrestricted cell cycle progression through retinoblastoma (RB) protein inactivation, while loss of ARF has been linked to p53 inactivation with subsequent malfunction in cell cycle regulation, apoptosis and DNA repair (Chin et al., 2006). The NRAS and BRAF genes are commonly mutated in sporadic primary cutaneous melanomas, with mutation frequencies between 4–50% (Platz et al., 2008) and 25–80% (Platz et al., 2008), respectively. Codon 61 is the most common position of NRAS alterations in melanoma, with frequent glutamine changes to either lysine, Q61K (c.181C>A), or arginine, Q61R (c.182A>G) (Omholt et al., 2002). Mutations in this residue lock the Ras protein in the GTP-bound state with subsequent continuous activation of its downstream effectors (Platz et al., 2008) through the Ras-Raf-MEK-ERK and Ras-PI3K-Akt pathways. Approximately 90% of reported BRAF mutations occur at residue 600, which is located in the activation domain of this kinase (Thomas, 2006). Current results from melanoma cohorts show that mutations in these genes are almost always mutually exclusive (Edlundh-Rose et al., 2006; Omholt et al., 2003; Platz et al., 2008). Moreover, a high rate of BRAF mutation is found also in nevi, suggesting a role in early stages of the neoplastic process (Pollock et al., 2003). Previously, a high frequency of NRAS mutations (95%) has been reported in Swedish familial melanoma cases with germline CDKN2A alterations (Eskandarpour et al., 2003). The association of BRAF somatic mutations with MC1R germline variants indicates an influence of constitutive genotype on the preferential acquisition of specific mutations during melanoma development (Landi et al., 2006). In line with this, cooperation between RAS and CDKN2A has been shown in animal models of melanoma (Chin et al., 1997). Since there is limited information on NRAS and BRAF mutations in familial melanoma we sought to assess their mutation frequency in melanomas from patients with different CDKN2A germline alterations. The study was performed on formalin-fixed, paraffin-embedded (FFPE) primary familial cutaneous melanomas originating from Brisbane, Australia (16 samples from 15 patients) and Genoa, Italy (3 patients/samples). Clinical and pathological characteristics are shown in Table 1. One patient with a CDKN2A L32P mutation had two melanomas originating from the trunk and upper extremity, respectively, while a single melanoma was analyzed from each of the other patients. Eight different germline CDKN2A mutations were present in the patients from whom the melanomas were analyzed (Table 2). Laser capture microdissection, DNA extraction, polymerase chain reaction (PCR) amplification, single strand conformation polymorphism (SSCP) and nucleotide sequence analyses of NRAS exon 2 and BRAF exon 15 were carried out as previously described (Jovanovic et al., 2008; Omholt et al., 2002; Omholt et al., 2003). Each mutation was confirmed by two independent PCR/SSCP analyses followed by sequence analysis performed in both directions. The study was approved by the Ethics Committees of the Queensland Institute of Medical Research, University of Genoa and Karolinska Institutet. Table 1 Patient and tumor characteristics Table 2 NRAS and BRAF genotypes in familial melanomas harboring CDKN2A germline mutations Three (16%) samples had NRAS residue 61 alterations (one Q61R and two Q61K substitutions) while 7 (37%) samples had valine to glutamic acid changes in amino acid 600 of BRAF (V600E; Table 2). The NRAS mutation frequency in this study was lower than we reported previously in melanomas from Swedish families with germline CDKN2A mutations (Eskandarpour et al., 2003). The reason for this is unclear. It could possibly be attributed to different origins of studied cohorts (Sweden versus Australia/Italy) and to different CDKN2A germline alterations in these two studies (the 112Argdup founder mutation is predominant in Swedish families, which is in contrast to genotypes reported here). However, we cannot exclude that technical factors, possibly related to the fragmented nature of DNA extracted from FFPE samples, may play a role in different rates of mutation detection. Intriguingly, all 3 tumors with NRAS mutations also had BRAF V600E mutations. The presence of both NRAS and BRAF V600E mutations in the same lesions is contrary to the current consensus that such mutations are almost always mutually exclusive in melanomas and other tumor types (Davies et al., 2002; Omholt et al., 2003; Thomas et al., 2007). However, Pollock et al (2003) observed concomitant NRAS and BRAF V600E mutations in 9% of nevi and suggested this might be due to different clonal nests of cells within these tumors carrying distinct mutations, a possibility that could also explain our findings. Although intriguingly, the joint presence of both NRAS and BRAF mutations was found only in tumors from patients with CDKN2A L32P mutations. In two of these tumors, NRAS and BRAF mutations (NRAS/BRAF: Q61K/V600E and Q61R/V600E) were found in two different DNA extracts while in one case, alterations of both genes (NRAS/BRAF: Q61K/V600E) were identified in the same DNA extract. Thus far, it is recognized that a mutation in either NRAS or BRAF is sufficient for activation of the Ras-Raf-MEK-ERK pathway, with mutant RAS having a 50-fold higher activation effect than mutant BRAF (Davies et al., 2002). Although we do not have any evidence that the NRAS and BRAF mutations found in the same DNA extract were coexisting in the same cells, it is possible that the L32P mutation in CDKN2A somehow permits cellular tolerance of these dual mutations. In conclusion, the NRAS and BRAF mutation rates we observed in familial melanomas were generally lower than most previous reports in sporadic melanoma but equal to those reported for primary melanomas of similar thickness (Goel et al., 2006; Shinozaki et al., 2004). Samples that harbored INK4A L32P substitutions also had high frequency of coexisting mutations in both NRAS and BRAF. This suggests that in some instances constitutional CDKN2A mutations affect the occurrence of somatic mutations in NRAS and BRAF, although further work is needed to substantiate this hypothesis.

Background: The incidence of melanoma continues to increase in many countries, and primary prevention of melanoma includes avoidance of sunburn as well as adequate sun protection behavior. The aim of this study was to examine the prevalence of self-reported sun protection behaviors and sunburn in users of the Internet, and to identify the demographic, clinical, and attitudinal/motivational correlates of sun protection behaviors. Methods: Self-report data were gathered on behalf of the GenoMEL consortium using an online survey available in 10 different languages, and 8,178 individuals successfully completed at least 80% of survey items, with 73% of respondents from Europe, 12% from Australia, 7% from the United States, 2% from Israel, and 6% from other countries. Results: Half of all respondents and 27% of those with a previous melanoma reported at least one severe sunburn during the previous 12 months. The strongest factors associated with sun protection behavior were perceived barriers to protection (β = −0.44/β = −0.37), and respondents who reported a positive attitude toward suntans were less likely to protect (β = −0.16/β = −0.14). Reported use of protective clothing and shade, as well as avoidance of midday sun exposure, were more strongly related to reduced risk of sunburn than sunscreen use. Conclusions: Despite widespread dissemination of public health messages about the importance of sun protection, a substantial proportion of this international sample, including respondents with a previous melanoma, reported inadequate sun protection behaviors resulting in severe sunburn. Impact: Future strategies to decrease sunburn should target the practical, social, and psychological barriers associated with nonuptake of sun protection. Cancer Epidemiol Biomarkers Prev; 19(9); 2199–210. ©2010 AACR.

The incidence of malignant melanoma is currently increasing faster than any other cancer and in 5-12% of cases occurs in a familial context in which the disease cosegregates as an autosomal dominant trait. To identify the location of genes that predipose individuals to familial melanoma (MLM), we have carried out linkage analysis in three large Australian melanoma pedigrees using 172 microsatellite markers spread across all autosomes. Three additional smaller families were typed for 70 of the same markers. In five of the six families we found lod scores between 1.0 and 2.3, which may provide evidence for the location of melanoma genes in proximity to some of these markers. If this turns out to be the case, these data potentially demonstrate that MLM is genetically heterogeneous since there was no marker for which all families gave significantly high LODs. These data provide the foundation for an exclusion map for melanoma and, more importantly, high-light areas of the genome for others to substantiate the potential positions of some of the genes that may be responsible for susceptibility to MLM.

Little is known about the correlation between the loss of p16 expression and tumor progression in familial melanoma; no systematic study has been conducted on p16 expression in melanocytic tumors from patients carrying germline CDKN2A mutations. We analyzed 98 early primary lesions from familial patients, previously tested for germline CDKN2A status, by quantitative immunohistochemistry using 3 p16 antibodies. We found that p16 expression was inversely correlated with tumor progression and was significantly lower in melanomas, including in situ lesions, than in nevi. Of other features analyzed, tumor thickness showed the most significant correlation with p16 levels. Lesions from mutation-negative patients displayed combined nuclear and cytoplasmic staining. However, some mutation-positive lesions (ie, G101W, 113insR, M53I, R24P, and 33ins24), including benign nevi, showed nuclear mislocalization, confirming previous studies suggesting that subcellular distribution indicates functional impairment of p16.

Familial melanoma (MLM) is sometimes found associated with the dysplastic nevus syndrome (DNS). Considerable controversy exists over the possible assignment of a cutaneous malignant melanoma/dysplastic nevus gene, designated CMM, to the distal short arm of chromosome 1, linked to the PND and D1S47 loci. To date, no support for linkage of MLM alone to these markers has been found; likewise no study has been able to exclude the entire region between PND and D1S47 from linkage to MLM. We have carried out linkage studies between markers on 1p and MLM in seven Australian kindreds; three of these are the largest reported worldwide. We have been able to exclude localization of an MLM gene from a 40-cM region that spans the interval between D1S47 and PND and extends approximately 15 cM on either side of these markers. In addition, we can exclude a region of about 20 cM around the MYCL1/D1S57 loci.

The overall incidence of melanoma is increasing world wide. We investigated whether there has been an increase in familial melanoma by studying age at onset among different birth cohorts in 18 melanoma kindreds linked to a predisposition gene ( MLM2 ) on chromosome 9. The cumulative incidence of melanoma was 21-fold higher (95% Cl 5·2-84 6) among subjects born after 1959 than in those born before 1900. The expected age of onset of the group born after 1959 was 24 years earlier (21 0 vs 45 0 years). These data support the notion that phenotypic penetrance of the MLM2 gene is increasing, presumably as a result of the interaction of sunlight exposure and mutation at this locus.

Although risk factors for primary cutaneous melanoma are well defined, relatively little is known about predictors for second primary melanoma. Given the rising incidence of this cancer, coupled with improvements in survival, there is a prevalent and growing pool of patients at risk of second primary melanomas. To identify the predictors of second primary melanoma, we followed a cohort of 1,083 Queensland patients diagnosed with incident melanoma between 1982 and 1990 and who completed a baseline questionnaire. During a median follow-up of 16.5 years, 221 patients were diagnosed with at least one additional primary melanoma. In multivariate analyses, second primary melanomas were associated with high nevus count (hazard ratio (HR), 2.91; 95% confidence interval (CI) 1.94–4.35), high familial melanoma risk (HR, 2.12; 95% CI 1.34–3.36), fair skin (HR, 1.51; 95% CI 1.06–2.16), inability to tan (HR, 1.66; 95% CI 1.13–2.43), an in situ first primary melanoma (HR, 1.36; 95% CI 0.99–1.87), and male sex (HR, 1.49; 95% CI 1.12–2.00). Patients whose first primary was lentigo maligna melanoma (HR, 1.80; 95% CI 1.05–3.07) or nodular melanoma (HR, 2.13; 95% CI 1.21–3.74) had higher risks of subsequent primaries than patients whose first primary tumor was superficial spreading melanoma. These characteristics could be assessed in patients presenting with first primary melanoma to evaluate risk of developing a second primary.