Clinical considerations on sentinel node biopsy in melanoma from an Italian multicentric study on 1,313 patients (SOLISM-IMI).

BACKGROUND: Although widely used for the management of patients with cutaneous melanoma, the sentinel lymph node (SLN) biopsy (SNB) procedure raises several issues. This study was designed to investigate: the predictive factors of SLN status, the false-negative (FN) rate, and patients' prognosis after SNB. PATIENTS AND METHODS: This is an observational, prospective study conducted on a large series of consecutive patients (n = 1,313) enrolled by 23 Italian centers from 2000 through 2002. A commonly shared protocol was adopted for the SNB surgical procedure and the SLN pathological examination. RESULTS: The SLN positive and false-negative (FN) rates were 16.9% and 14.4%, respectively (median follow-up, 4.5 years). At multivariable logistic regression analysis, the frequency of positive SLN increased with increasing Breslow thickness (p < 0.0001) and decreased in patients with melanoma regression (p = 0.024). At the multivariable Cox regression analysis, SLN status was the most important prognostic factor (hazards ratio (HR) = 3.08) for overall survival; the other statistically significant factors were sex, age, Breslow thickness, and Clark's level. Considering SLN and NSLN status, including FN cases, we identified four groups of patients with different prognoses. The 5-year overall survival of patients with positive SLNs was 71.3% in those with negative nonsentinel lymph nodes (NSLNs) and 50.4% if NSLNs were positive. CONCLUSIONS: Regression in the primary melanoma seems to be a protective factor from metastasis in the SLN. When correctly calculated, the SNB FN rate is 15-20%. Furthermore, the SNB is important to more precisely assess the prognosis of patients with melanoma.

The impact of lymphoscintigraphy technique on the outcome of sentinel node biopsy in 1,313 patients with cutaneous melanoma: an Italian Multicentric Study (SOLISM-IMI).

UNLABELLED: An observational multicentric Italian trial on sentinel node biopsy (SNB) in melanoma patients was performed to diffuse a common SNB protocol nationwide (Italy). We report herein the results of this trial. The influence of some technical aspects on the outcome of SNB was also investigated, because a certain degree of variability was accepted in performing lymphoscintigraphy. METHODS: From January 2000 to December 2002, 1,313 consecutive patients with primary cutaneous melanoma (Breslow thickness, >1.0 mm or <1.0 mm but with ulceration, Clark level IV-V, presence of regression) were enrolled by 23 centers. One half to 1 mL of 99mTc-labeled human albumin colloid, at a suggested dosage of 5-15 or 30-70 MBq, was injected intradermally, closely around the scar, the same day or the day before SNB. Intraoperatively, Patent blue was associated when a definitive wide excision of the primary was required. A positive sentinel node (SN) was defined when containing melanoma cells detected by either hematoxylin-eosin or immunohistochemistry (S100 and HMB45 antibodies). All patients underwent regular follow-up. False-negative cases were considered when lymph node metastases occurred in the same lymphatic basin of SN biopsy (SNB) during follow-up. A quality control program has been performed for the surgical procedure and for the histologic diagnosis. RESULTS: The SN identification rate was 99.3%. The axilla was the site of the SN in 52.5% of the cases. The mean number of SNs was 2.0 (range, 1-17) and only 1 node was removed in 45.4%. The positivity and false-negative rates were 16.9% and 14.7%, respectively (median follow-up, 31 mo). On multivariate analysis (logistic and linear regression) only the number of peritumor injections was inversely associated with the number of excised SNs (P = 0.002), whereas none of the technical variables showed an independent impact on SN status when Breslow thickness was included as a control variable. CONCLUSION: The number of peritumor injections seems to influence the outcome of lymphoscintigrapy in melanoma patients undergoing SNB. If these results are confirmed in a controlled trial, 3 injections at least should be recommended.

Rare missense variants in POT1 predispose to familial cutaneous malignant melanoma.

Although CDKN2A is the most frequent high-risk melanoma susceptibility gene, the underlying genetic factors for most melanoma-prone families remain unknown. Using whole-exome sequencing, we identified a rare variant that arose as a founder mutation in the telomere shelterin gene POT1 (chromosome 7, g.124493086C>T; p.Ser270Asn) in five unrelated melanoma-prone families from Romagna, Italy. Carriers of this variant had increased telomere lengths and numbers of fragile telomeres, suggesting that this variant perturbs telomere maintenance. Two additional rare POT1 variants were identified in all cases sequenced in two separate Italian families, one variant per family, yielding a frequency for POT1 variants comparable to that for CDKN2A mutations in this population. These variants were not found in public databases or in 2,038 genotyped Italian controls. We also identified two rare recurrent POT1 variants in US and French familial melanoma cases. Our findings suggest that POT1 is a major susceptibility gene for familial melanoma in several populations.

Duplication of CXC chemokine genes on chromosome 4q13 in a melanoma-prone family.

Copy number variations (CNVs) have been shown to contribute substantially to disease susceptibility in several inherited diseases including cancer. We conducted a genome-wide search for CNVs in blood-derived DNA from 79 individuals (62 melanoma patients and 17 spouse controls) of 30 high-risk melanoma-prone families without known segregating mutations using genome-wide comparative genomic hybridization (CGH) tiling arrays. We identified a duplicated region on chromosome 4q13 in germline DNA of all melanoma patients in a melanoma-prone family with three affected siblings. We confirmed the duplication using quantitative PCR and a custom-made CGH array design spanning the 4q13 region. The duplicated region contains 10 genes, most of which encode CXC chemokines. Among them, CXCL1 (melanoma growth-stimulating activity α) and IL8 (interleukin 8) have been shown to stimulate melanoma growth in vitro and in vivo. Our data suggest that the alteration of CXC chemokine genes may confer susceptibility to melanoma.

Genome-wide association study identifies three new melanoma susceptibility loci.

We report a genome-wide association study for melanoma that was conducted by the GenoMEL Consortium. Our discovery phase included 2,981 individuals with melanoma and 1,982 study-specific control individuals of European ancestry, as well as an additional 6,426 control subjects from French or British populations, all of whom were genotyped for 317,000 or 610,000 single-nucleotide polymorphisms (SNPs). Our analysis replicated previously known melanoma susceptibility loci. Seven new regions with at least one SNP with P < 10(-5) and further local imputed or genotyped support were selected for replication using two other genome-wide studies (from Australia and Texas, USA). Additional replication came from case-control series from the UK and The Netherlands. Variants at three of the seven loci replicated at P < 10(-3): an SNP in ATM (rs1801516, overall P = 3.4 × 10(-9)), an SNP in MX2 (rs45430, P = 2.9 × 10(-9)) and an SNP adjacent to CASP8 (rs13016963, P = 8.6 × 10(-10)). A fourth locus near CCND1 remains of potential interest, showing suggestive but inconclusive evidence of replication (rs1485993, overall P = 4.6 × 10(-7) under a fixed-effects model and P = 1.2 × 10(-3) under a random-effects model). These newly associated variants showed no association with nevus or pigmentation phenotypes in a large British case-control series.