Trends in cutaneous malignant melanoma in Sweden 1997-2011: thinner tumours and improved survival among men

BACKGROUND

Both patient survival and the proportion of patients diagnosed with thin cutaneous malignant melanoma (CMM) have been steadily rising in Sweden as in most Western countries, although the rate of improvement in survival appears to have declined in Sweden at the end of the last millennium.

OBJECTIVES

To analyse the most recent trends in the distribution of tumour thickness (T category) as well as CMM-specific survival in Swedish patients diagnosed during 1997-2011.

METHODS

This nationwide population-based study included 30,590 patients registered in the Swedish Melanoma Register (SMR) and diagnosed with a first primary invasive CMM during 1997-2011. The patients were followed through 2012 in the national Cause of Death Register.

RESULTS

Logistic and Cox regression analyses adjusting for age at diagnosis, tumour site and healthcare region were carried out. The odds ratio for being diagnosed with thicker tumours was significantly reduced (P < 0·001) and the CMM-specific survival significantly improved in men diagnosed during 2007-2011 compared with men diagnosed during 1997-2001 (hazard ratio = 0·81; 95% confidence interval 0·72-0·91; P < 0·001), while the corresponding differences for women were not significant. Women were diagnosed with significantly thicker tumours during 2002-2006 and a tendency towards decreased survival was observed compared with those diagnosed earlier (during 1997-2001) and later (during 2007-2011).

CONCLUSIONS

In Sweden, the CMMs of men are detected earlier over time and this seems to be followed by an improved CMM-specific survival for men. Women are still diagnosed with considerably thinner tumours and they experience a better survival than men.

One course of adjuvant BEP in clinical stage I nonseminoma mature and expanded results from the SWENOTECA group

BACKGROUND

SWENOTECA has since 1998 offered patients with clinical stage I (CS I) nonseminoma, adjuvant chemotherapy with one course of bleomycin, etoposide and cisplatin (BEP). The aim has been to reduce the risk of relapse, sparing patients the need of toxic salvage treatment. Initial results on 312 patients treated with one course of adjuvant BEP, with a median follow-up of 4.5 years, have been previously published. We now report mature and expanded results.

PATIENTS AND METHODS

In a prospective, binational, population-based risk-adapted treatment protocol, 517 Norwegian and Swedish patients with CS I nonseminoma received one course of adjuvant BEP. Patients with lymphovascular invasion (LVI) in the primary testicular tumor were recommended one course of adjuvant BEP. Patients without LVI could choose between surveillance and one course of adjuvant BEP. Data for patients receiving one course of BEP are presented in this study.

RESULTS

At a median follow-up of 7.9 years, 12 relapses have occurred, all with IGCCC good prognosis. The latest relapse occurred 3.3 years after adjuvant treatment. The relapse rate at 5 years was 3.2% for patients with LVI and 1.6% for patients without LVI. Five-year cause-specific survival was 100%.

CONCLUSIONS

The updated and expanded results confirm a low relapse rate following one course of adjuvant BEP in CS I nonseminoma. One course of adjuvant BEP should be considered a standard treatment in CS I nonseminoma with LVI. For patients with CS I nonseminoma without LVI, one course of adjuvant BEP is also a treatment option.

Individualized intensification of treatment based on tumor marker decline in metastatic nonseminomatous germ cell testicular cancer (NSGCT): A report from the Swedish Norwegian Testicular Cancer Group, SWENOTECA

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Background: From July 1995 to December 2003, 602 adult patients from Sweden and Norway with metastatic testicular NSGCT were included in a population-based multicenter SWENOTECA protocol with strict guidelines for staging, treatment and follow-up. Methods: The basic strategy of this protocol was to individualize treatment according to AFP and β-HCG decline (t1/2). Satisfactory response to treatment was defined as a t½ for AFP ≤ 7 days and/or β-HCG ≤ 3 days. Initial treatment for all patients was 2 courses of standard BEP. Tumor markers were analyzed once a week during treatment. Patients with satisfactory response went on with BEP while patients with unsatisfactory t1/2 received intensified treatment in two steps with addition of ifosfamide (BEP-if/PEI) in step 1. If still unsatisfactory response the treatment was intensified according to step 2 involving high-dose chemotherapy with stem cell rescue. Postchemotherapy surgery was performed according to protocol guidelines. Results: 99,7% (602 of 604) of all patients with metastatic testicular NSGCT in the population were included in the protocol. Median FU was 72 months. 75% of the patients were treated with BEP, median 4 courses, without intensification, 19% according to intensification step 1 and 6% according to intensification step 2. Five year progression free survival (PFS), cancer specific survival (CSS) and overall survival (OS) grouped according to IGCCCG prognostic score are given in the Table below. There was no significant difference in PFS between the good and intermediate risk group. Death due to all causes was 10,1% (n=61) and treatment related deaths were 1,3 % (n=8). Conclusions: Our results, in a population based patient material, with individualized treatment based on tumor marker decline, are highly encouraging in all risk groups, but most notably in the intermediate risk group.

[Table: see text]

No significant financial relationships to disclose.

Interaction by cholestyramine on the uptake of hydrocortisone in the gastrointestinal tract

An absolute reduction of the plasma cortisol levels and a delay of the peak concentrations were recorded in 10 healthy subjects, when a bile-sequestering anionic exchange resin, cholestyramine, was given prior to a single oral hydrocortisone dose, indicating that the resin interferes with the uptake of a neutral sterol in the human gastrointestinal tract. The possibility of a direct binding of drug to resin is supported by the affinity of hydrocortisone to cholestyramine in vitro, which was uninfluenced by the presence of sodium taurocholate. Cholestyramine significantly delayed the gastric emptying of a glucose solution, indicating that the resin not only decreases but also delays hydrocortisone absorption. Careful supervision is recommended when treatment with cholestyramine is given concomitant to neutral sterol drugs.

The value of PET-CT (positron emission tomography) in the treatment of metastatic renal cell carcinoma with sorafenib

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Background: Sorafenib is a new potent multikinase inhibitor directed against both tumour proliferation and angiogenesis. Clinical benefit has been shown in 75% of patients with metastatic renal cell carcinoma. The aim of this study was to evaluate this new treatment with PET-CT with fluorodeoxyglucose (FDG), since the use of only CT measurements has been questioned. Methods: 10 patients (8 male, 2 female, 49–72 years) with metastatic renal cell carcinoma (9 clear cell, 1 chromophobe). All had progressive disease (8 after interferon). Sorafenib 400 mg b.i.d was given orally. FDG-PET-CT scan was performed from head-proximal thigh before treatment and after one month. Up to 6 target lesions in each patient were studied. The sum of the largest diameters was calculated from CT images for each patient. To evaluate the glucose uptake, a region of interest (roi) was designed for each leasion on the initial PET on the transverse section where the lesion appeared to be largest and/or most intense. Using the same roi for subsequent examinations the mean glucose uptake/mean cerebellar uptake was calculated. For each patient the mean change from baseline was calculated. Results: After one month of treatment the sum of tumour diameters measured by CT was mean 85% (53–110%) of the initial value. Measured by PET the mean glucose uptake at one month was mean 73% (29–100%) of the initial value. Seven patients had skeletal lesions. These were often difficult to measure on CT and only small changes were detected. Using PET the mean uptake in skeletal lesions was 77% (62–104%) at one month. Conclusions: Early effects of sorafenib treatment in metastatic renal cell carcinoma can be detected and quantified by PET-CT. Especially in skeletal lesions PET-CT exhibits considerable benefits over CT by visualizing responses otherwise missed. Future studies will reveal if a decrease in tumour glucose uptake at one month correlates with the more clinically relevant endpoints PFS and OS.

[Table: see text]

O6-methylguanine-DNA-methyltransferase expression and gene polymorphisms in relation to chemotherapeutic response in metastatic melanoma

In a retrospective study, O⁶-methylguanine-DNA-methyltransferase (MGMT) expression was analysed by immunohistochemistry using monoclonal human anti-MGMT antibody in melanoma metastases in patients receiving dacarbazine (DTIC) as single-drug therapy or as part of combination chemotherapy with DTIC–vindesine or DTIC–vindesine–cisplatin. The correlation of MGMT expression levels with clinical response to chemotherapy was investigated in 79 patients with metastatic melanoma. There was an inverse relationship between MGMT expression and clinical response to DTIC-based chemotherapy (P=0.05). Polymorphisms in the coding region of the MGMT gene were also investigated in tumours from 52 melanoma patients by PCR/SSCP and nucleotide sequence analyses. Single-nucleotide polymorphisms (SNPs) in exon 3 (L53L and L84F) and in exon 5 (I143V/K178R) were identified. There were no differences in the frequencies of these polymorphisms between these melanoma patients and patients with familial melanoma or healthy Swedish individuals. Functional analysis of variants MGMT-I143V and -I143V/K178R was performed by in vitro mutagenesis in Escherichia coli. There was no evidence that these variants decreased the MGMT DNA repair activity compared to the wild-type protein. All melanoma patients with the MGMT 53/84 polymorphism except one had tumours with high MGMT expression. There was no significant correlation between any of the MGMT polymorphisms and clinical response to chemotherapy, although an indication of a lower response rate in patients with SNPs in exon 5 was obtained. Thus, MGMT expression appears to be more related to response to chemotherapy than MGMT polymorphisms in patients with metastatic melanoma.

Neoadjuvant, adjuvant and palliative treatment of gastrointestinal stromal tumours (GIST) with imatinib: a centre-based study of 17 patients

Malignant gastrointestinal stromal tumours (GIST) have a poor prognosis. Since these tumours are resistant to conventional radiation and chemotherapy, surgery has been the mainstay of treatment. However, surgery is usually inadequate for the treatment of malignant GIST. Imatinib, a KIT tyrosine kinase inhibitor, has recently been found to have a dramatic antitumour effect on GIST. In this centre-based study of 17 consecutive patients with high-risk or overtly malignant GIST, imatinib was used in three different settings - palliatively, adjuvantly, and neoadjuvantly. The treatment was found to be safe and particularly effective in tumours with activating mutations of exon 11 of the KIT gene. Clinical response to imatinib treatment correlated morphologically to tumour necrosis, hyalinisation, and reduced proliferative activity. The value of neoadjuvant imatinib treatment was illustrated in one case.

Mixed chimaerism is common at the time of acute graft-versus-host disease and disease response in patients receiving non-myeloablative conditioning and allogeneic stem cell transplantation

We report the clinical outcome and results of chimaerism analysis in various cell lineages of 30 patients given non-myeloablative conditioning, followed by allogeneic stem cell transplantation (SCT). The commonest diagnoses were chronic myelogenous leukaemia (n = 11) and solid tumours (n = 11). Twenty-one patients received SCT from human leucocyte antigen (HLA)-identical siblings and nine from matched unrelated donors. Median patient age was 53 (28-77) years. Four non-myeloablative protocols were used, including fludarabine (30 mg/m2 x 3-6), busulphan (4 mg/kg x 2), cyclophosphamide (Cy) (30 mg/kg/day x 2) or total body irradiation (2 Gy), and anti-thymocyte globulin. The patients were analysed by polymerase chain reaction (PCR) analysis of minisatellites on days 14, 21 and 28, then every other week up to 3 months and monthly thereafter. All samples were cell separated for T, B and myeloid cells using immunomagnetic beads. Eighteen patients were alive at a median follow-up of 11 (6-20) months. Acute graft-versus-host disease (GVHD) occurred in 22 patients. Eighteen of the 22 patients with acute GVHD showed mixed chimaerism (MC) in the T-cell fraction at the time of acute GVHD. However, all patients with acute GVHD showed donor chimaerism (DC) in the T-cell fraction median 76 (7-414) days after onset versus three out of eight patients without acute GVHD, P < 0.001]. Disease response was diagnosed in 15 patients, median 100 (37-531) days after SCT. At the time of disease response, six out of 15 patients showed MC in the T-cell fraction. In conclusion, mixed chimaerism in the T-cell fraction is common at the time of acute GVHD and disease response in patients conditioned with non-myeloablative therapy.

Haplotype analysis and age estimation of the 113insR CDKN2A founder mutation in Swedish melanoma families

Germline mutations in the CDKN2A tumor suppressor gene located on 9p21 have been linked to development of melanomas in some families. A germline 3-bp insertion in exon 2 of CDKN2A, leading to an extra arginine at codon 113 (113insR), has been identified in 17 Swedish melanoma families. Analysis of 10 microsatellite markers, spanning approximately 1 Mbp in the 9p21 region, showed that all families share a common allele for at least one of the markers closest to the CDKN2A gene, suggesting that the 113insR mutation is an ancestral founder mutation. Differences in the segregating haplotypes, due to meiotic recombinations and/or mutations in the short-tandem-repeat markers, were analyzed further to estimate the age of the mutation. Statistical analysis using a maximum likelihood approach indicated that the mutation arose 98 generations (90% confidence interval: 52-167 generations), or approximately 2,000 years, ago. Thus, 113insR would be expected to have a more widespread geographic distribution in European and North American regions with ancestral connections to Sweden. Alternatively, CDKN2A may lie in a recombination hot spot region, as suggested by the many meiotic recombinations in this narrow approximately 1-cM region on 9p21.

CDKN2A germ-line mutations in individuals with multiple cutaneous melanomas

Germ-line CDKN2A mutations are present in some kindreds with hereditary cutaneous melanoma, and in Sweden a founder mutation with an extra arginine in codon 113 (113insR) has been identified. We screened 80 individuals with at least two primary cutaneous melanomas, who were identified mainly by a search of a regional cancer registry, for germ-line CDKN2A mutations. In nine patients, CDKN2A alterations that may contribute to melanoma predisposition were detected. In six individuals with a family history of melanoma, the 113insR founder mutation was present. One patient, who also had a family history of melanoma, had a 24-bp deletion that included codons 62-69. An in vitro binding assay established that the resulting mutant p16 protein was unable to bind cyclin-dependent kinase 4 and cyclin-dependent kinase 6. Two patients without a family history of melanoma had CDKN2A alterations: (a) one had a mutation in the 5' noncoding sequence (-14C/T); and (b) the other had an insertion of an extra T in codon 28, which results in a stop signal in codon 43. The median age at diagnosis of the first melanoma was significantly lower, the number of primary melanomas was significantly higher, and the presence of a family history of melanoma was significantly more common in patients with CDKN2A mutations than in those without germ-line mutations. The proportion of CDKN2A mutation carriers was significantly higher among patients treated for three or more primary melanomas compared with those with two tumors only. We conclude that mutation screening of individuals with multiple primary melanomas is a useful strategy to identify new melanoma kindreds with CDKN2A germ-line mutations.

Sensitivity to extrinsically supplied interferon and the endogenous expression of interferon in melanoma cell lines

Interferons (IFNs) have been shown to Induce loss of growth potential in melanoma cell lines. However, human melanomas have shown limited responsiveness to clinical therapy with IFN. In a previous study on melanoma cell lines we found that greatest sensitivity to IFN was found in cell lines with the greatest number of copies of chromosome 9p, where the IFN gene family is located. In the present study the expression In melanoma cell lines of IFN genes, IFN receptor genes and standard control genes (beta-actin, glyceraldehyde-3-phosphate dehydrogenase, 18S rRNA and cyclophilin) was investigated using the reverse transcription-polymerase chain reaction, together with an exogenous standard (cyclophllin armoured RNA). We found that the sensitivity to extrinsically supplied IFN seems to correlate with the expression of endogenous IFN genes. The two melanoma cell lines producing the highest relative amount of IFN mRNA transcripts also demonstrated the most marked response to extrinsically supplied IFN. We hypothesize that tumours with enhanced endogenous IFN production may respond more positively to IFN treatment.

Dacarbazine-vindesine versus dacarbazine-vindesine-cisplatin in disseminated malignant melanoma. A randomised phase III trial

In a multicentre phase III study of disseminated malignant melanoma performed in Sweden and Norway, 326 patients were randomised to receive treatment with the combination dacarbazine [DTIC] (D) and vindesine (V) with or without the addition of cisplatin (P). D was given intravenously (i.v.) at a dose of 250 mg/m2 days 1-5 every 4 weeks and V was given i.v. at a dose of 3.0 mg/m2 day 1 weekly. P was given i.v. at a dose of 100 mg/m2 day 1 every 4 weeks. There was no statistically significant difference in overall survival between the treatment arms (P = 0.22). Increased toxicity was observed in the treatment arm containing P of which leucopenia, alopecia and nausea/vomiting were the most pronounced. The median time to progression was significantly longer in patients treated with DVP (4.2 versus 2.2 months, P = 0.007). In conclusion, adding P to DV did not change overall survival but did significantly increase toxicity.

Risk-adapted treatment of clinical stage 1 non-seminoma testis cancer

250 patients with clinical stage 1 non-seminomatous germ cell tumours of the testis (NSGCT 1) were included into a prospective multicentre protocol during 1990-1994 and treated according to three risk strata: patients without tumour cell invasion of vascular structures in the testis (VASC-) and elevated serum AFP levels (AFP+) at orchiectomy were considered low risk (LR) and only observed closely. VASC- and AFP- or VASC+ and AFP+ patients were presumed intermediate risk (IR) and pathologically staged (PS) by retroperitoneal lymph node dissection (RPLND). VASC+ and AFP-patients were regarded as high risk (HR) and received adjuvant chemotherapy (PEB x 3). At a median observation time of 40 (7-68) months, all patients were alive and without evidence of active germ cell cancer. The actuarial relapse rate in the 106 LR patients was 22%, and 70% (14/20) had elevated serum tumour markers at relapse. One of 32 (3%) HR patients relapsed with a resectable retroperitoneal mature teratoma despite adjuvant chemotherapy. Only 14% of the 99 IR patients who underwent RPLND had PS2 disease, and the actuarial relapse rate in 85 PS1 patients was 18%. This multicentre study demonstrated that excellent therapeutic outcome is possible when 18 comparatively small urological and oncological centres follow a strict and formal cancer care programme. The useful prognostic effect of VASC was once again verified. Pathological staging by RPLND in NSGCT1 is, in our opinion, not necessary, with presumed low-risk patients offered surveillance and high-risk patients offered adjuvant chemotherapy.

Action of interferon alpha and beta on four human melanoma cell lines in vitro

Four human melanoma cell lines with different copy numbers of chromosomes 9 and 21q, as studied by the G-band technique, fluorescent in situ hybridisation (FISH) and Polymerase chain reaction (PCR), were tested for their sensitivity to Interferon-alpha (IFN-alpha) and Interferon-beta (IFN-beta) in relation to dosage of interferon genes (#9) and interferon receptor genes (#21p). The two most sensitive cell lines were those containing the highest numbers of #9 per cell, while the number of #21q copies (receptor genes) seemed to have no influence on the interferon sensitivity.

Characterization of four melanoma cell lines with electron microscopy, immunocytochemistry, cytogenetics, flow cytometry, and southern analysis

Four cell lines established from human metastatic malignant melanoma, derived from four patients, were analyzed. Ultrastructurally and immunocytochemically, the cultured tumor cells had retained characteristic features of melanocytes and of the primary malignant melanomas. The genetic stability was investigated by repeated flow-cytometric and cytogenetic analyses over 24 months of continuous cultivation. The DNA indices ranged from 1.7 to 2.1 and were stable during the entire period. The same was true for the karyotypes, which had modal numbers ranging from 50 to 84. The most common types of abnormalities were: isochromosomes i(1q), i(9q), translocations (1;17) and (3;6), and other aberrations (1p+,4p+,5p+,11p+,11q-,11q+). Abnormalities involving chromosome 1 were present in all cell lines, but loss of genetic material from chromosome 1p was demonstrated in only one of four cell lines when tested by the Southern blotting technique using a lambda MS1 probe.

Regional distribution of melanocytic naevi in relation to sun exposure, and site-specific counts predicting total number of naevi

The role of exposure to ultraviolet light in the formation of melanocytic naevi was analysed by investigating the regional naevus distribution in 310 subjects (30-50 years) from a Swedish census file. The lateral aspect of the arms and the back had the largest concentration of naevi. The mean naevus count per unit surface area was higher in intermittently exposed than in rarely exposed skin (p less than 0.001), while the lowest mean count was found in chronically exposed skin. These results support the idea that intermittent exposure to ultraviolet light has a "naevogenic" effect while chronic exposure might be protective. Dysplastic naevi had a distribution pattern quite different from common naevi. Considering the distribution pattern solely, dysplastic naevi seem to develop independently of exposure to ultraviolet light. The numbers of naevi in different skin areas were tested for their power in predicting the total body naevus count. The strongest correlations were found between total counts and counts on the anterior surface of the thighs and the lateral aspect of the arms. Counts from any of these areas will provide a practical and satisfactory estimate of the total number of naevi.

Association of ploidy and cell proliferation, Dukes' classification, and histopathological differentiation in adenocarcinomas of colon and rectum

OBJECTIVES

To find out if there is an association between DNA indexes and DNA synthesis (S) phase measurements and Dukes' classification and histopathological differentiation in colorectal cancers, and to investigate the interrelationship between DNA indexes and S phase measurements.

DESIGN

Prospective open study.

MATERIAL

182 colorectal carcinomas in 181 consecutive patients.

INTERVENTION

Tumours biopsied immediately after resection or at rectoscopy or colonoscopy.

RESULTS

One or more aneuploid cell populations were found in 113 of 182 carcinomas (62%). There was no correlation between Dukes' stage and either degree of differentiation or S phase measurements, but there were significant correlations between S phase measurements and histological grading (p less than 0.05), and between the percentage of cells in the S phase and the DNA index when values for both diploid and aneuploid tumours were included (p less than 0.001).

CONCLUSION

The degree of aneuploidy indicates how far tumour cells have progressed in their cellular disarrangement, and information about a tumour's proliferative capacity is given by the S phase measurements.

Regional distribution of common and dysplastic naevi in relation to melanoma site and sun exposure. A case-control study

The frequency of melanoma (CMM), and of common and dysplastic naevi (CN and DN) in areas of skin chronically, intermittently and rarely exposed to UV light was investigated in 121 melanoma patients (30-50 years) and 310 controls. Both cases and controls had significantly more CN in intermittently exposed areas than in areas chronically or rarely exposed. The ratio of observed to expected number of CMM was also highest in intermittently exposed skin (1.3 compared to 0.8 in chronically exposed and 0.5 in rarely exposed areas). Thus, intermittent UV exposure seems to have the most potent 'naevogenic' as well as carcinogenic effect on melanocytes. Nineteen per cent of controls and 56% of cases had naevi fulfilling the clinical criteria for DN. The distribution pattern of DN was clearly different from that of CN and does not accord with the idea that UV light is a major aetiological factor for DN. The probability of CMM significantly increased with the degree of relative clustering of CN (p less than 0.05) and of DN (p less than 0.01). This co-variation of naevi and CMM over the body surface might be the result of the local insults to the melanocyte system caused by UV light and/or to the fact that naevi are precursor lesions of CMM.

Prevalence of common and dysplastic naevi in a Swedish population

The naevus profile was examined in a Swedish population that was randomly selected from a census file. The participation rate was considered high at 82%. The number of common naevi (CN) and the prevalence of dysplastic naevi (DN) were investigated in 379 subjects (aged 30-50 years). The mean total body count of CN greater than or equal to 2 mm was 67 (range 1-300). As many as 22% of the population had 100 naevi or more and only 18% had less than 25. The counts were not influenced by age or sex. DN were diagnosed clinically in 18% (CI 14-22%) of the subjects and histologically in 8% (CI 5-11%). Subjects with dysplastic naevi had a significantly larger number of common naevi and a more sun-sensitive skin type than subjects without DN, P less than 0.001.

UVB irradiation induces melanocyte increase in both exposed and shielded human skin

This study demonstrates for the first time in humans that UV light induces an increase of the melanocyte population in exposed skin as well as in shielded areas. Because an increased mitotic activity could promote tumor development, UV exposure might play a role in melanoma development not only in exposed but also in covered skin. In addition, it was found that subjects who initially had a small melanocyte population showed a larger increase in both exposed and covered skin compared to those with a high initial density. Individuals with a low density might therefore constitute a risk group for the development of malignant melanoma. These findings support the view that infrequent periods of intensive UV irradiation might be more harmful than regular exposure.

Urinary Excretion of 5-S-Cysteinyldopa in Relation to Skin Type, UVB-induced Erythema, and Melanocyte Proliferation in Human Skin

5-S-Cysteinyldopa (5-S-CD) is found in all pigment-producing cells and is the major precursor of phaeomelanin. However, the melanocyte specificity of the compound has been questioned. In order to elucidate the origin of 5-S-CD, we have now systematically studied the relationship between the 5-S-CD excretion in urine and the size of the melanocyte organ, UV-induced melanocyte proliferation, skin type, and the erythemal reaction. The skin type had no influence on the basal excretion of 5-S-CD. There was no significant correlation between the basal 5-S-CD excretion and the size of the melanocyte organ; that is, the number of skin melanocytes and nevi. During the irradiation, subjects with skin type II developed a more pronounced erythema (p less than 0.01) and had a significantly higher 5-S-CD excretion than those with skin type III-IV (p less than 0.01). No correlation was found between 5-S-CD excretion and UV-induced melanocyte proliferation. The lack of correlation between the basal 5-S-CD excretion and skin type or number of melanocytes suggests that the basal 5-S-CD in urine is mainly of extra-melanocytic origin. Our findings favor the view that the increase in 5-S-CD excretion during UV irradiation is due to UV damage.

UVB-induced melanocyte proliferation and 5-S-cysteinyldopa excretion in dysplastic nevus syndrome

This is the first in vivo study of the effects of UV on the epidermal melanocytes in dysplastic nevus syndrome (DNS). Eleven DNS patients and 22 healthy subjects were given total body UVB irradiation 8 times during 17 days and the melanocyte population was estimated in biopsies from shielded and irradiated skin. There was a doubling of the melanocyte counts in irradiated skin and a less pronounced but significant increase in the shielded skin area. The urinary excretion of 5-S-cysteinyldopa (5-S-CD) was measured before, during and after the irradiation period. The 5-S-CD excretion reached a maximum after 2 weeks of irradiation and returned towards the basal value after the irradiation period. We were not able to document any abnormal melanocytic UV response in DNS patients before, during or after the irradiation.