MOLECULAR ANALYSIS OF A SERIES OF ACRAL MELANOMAS IN SINGAPORE

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1 MOLECULAR ANALYSIS OF A SERIES OF ACRAL MELANOMAS IN SINGAPORE PoYin Tan Inny Busmanis Dept of Anatomical Pathology, Lynette Oon Head, Molecular Lab Singapore General Hospital

2 ETHNIC GROUPS IN SINGAPORE Others,.% Indian, 9.% Malay,.% Chinese, 7.% Source: Singapore Department of Statistics, 0

3 ? What is the Distribution of the Different Subtypes of Melanoma in the Singapore Population % Cutaneous 0 Acral 0 Mucosal 77 9* High % acral and mucosal subtypes * 9 cases melanoma retrieved from SGH files over year period

4 ? How do Melanoma Subtypes Relate to Ethnic Groups in Singapore Ethnic Group Acral Mucosal Cutaneous Chinese 7 50 Caucasian 0 9 Malay Indian Others 9 Total 7

5 ? How do Melanoma Subtypes Relate to Ethnic Groups in Singapore Ethnic Group Acral Mucosal Cutaneous Chinese 7 (%) 50 Caucasian 0 9 Malay Indian Others 9 Total 7

6 ? How do Melanoma Subtypes Relate to Ethnic Groups in Singapore Ethnic Group Acral Mucosal Cutaneous Chinese 7 (9%) 50 Caucasian 0 9 Malay Indian Others 9 Total 7

7 ? How do Melanoma Subtypes Relate to Ethnic Groups in Singapore Ethnic Group Acral Mucosal Cutaneous Chinese 7 50 (5%) Caucasian 0 9 Malay Indian Others 9 Total 7

8 ? How do Melanoma Subtypes Relate to Ethnic Groups in Singapore Ethnic Group Acral Mucosal Cutaneous Chinese 7 (%) 50 Caucasian 0 9 Malay Indian Others 9 Total 7

9 ? How do Melanoma Subtypes Relate to Ethnic Groups in Singapore Ethnic Group Acral Mucosal Cutaneous Chinese 7 50 Caucasian 0 9 (%) Malay Indian Others 9 Total 7

10 Ethnic Groups Represented in the Molecular Analysis Cases (0 total) 7 Chinese (7.%) Caucasian 7 Malay Indian 5 Others Indonesian Philipino Vietnamese

11 ? What were the Categories of Melanoma According to Ethnic Group in the Molecular Cases Chinese Caucasian Malay Indian Others Cutaneous Acral 5 0 Mucosal 5 Total 0 Ranking of different types of melanoma remains the same Chinese majority in each type remains similar ; 0% skin % acral 7% mucosal Within this molecular subset the small number of Caucasians also had other tumour categories, so incidence of skin melanoma less, at 7%

12 ? What Subtypes of Melanoma are Represented in the 5 Molecular Acral Group Cases ALM Nodular 0 Desmoplastic Lymph node metastasis with no residual disease at original site 5 Of all Acral location tumours: 5 cases BRAF cases ckit

13 Molecular Results According to Histologic Subtypes of Acral Tumour Subtype BRAF ckit + + inconclusive ALM 0 5 Nodular 0 Desmoplastic No residual Total 5 Total

14 Molecular Results of Acral ALM and Nodular Subtypes Subtype BRAF ckit + + inconclusive ALM 0 5 Nodular 0 BRAF +ve cases: ALM V00E % (/) Each T>A ckit +ve cases: ALM % (5/5) Nodular 0% (/0) Each T>A? What is the Incidence of BRAF & ckit Mutations in the Exclusively Chinese Ethnic Group & ALL Acral Location Subtypes BRAF +ve ckit +ve 0% (/0) % (/) Exon x Exon x Exon 7 x

15 ? How do the BRAF & ckit Mutational Rates in Chinese, Acral Location Compare with the Mutation Status in Chinese with Cutaneous Melanoma Cutaneous: Ethnic group BRAF ckit + + Inconclusive Chinese 9 Caucasian 5 Malay Others Of ALL cutaneous cases BRAF + ve rate 55% (/) IF Caucasians excluded, BRAF +ve rate 5% (/0) Only total cases underwent ckit analysis; NIL +ve; one inconclusive

16 ? What Were the BRAF Results According to Histologic Subtypes of Cutaneous Melanoma Subtype Nodular BRAF + SSM LM Desmoplastic No residual disease 7 Note: Ckit numbers too small for analysis

17 ? So How do the Singapore Results Compare with Other Asian & Caucasian Populations As expected, a higher proportion of acral & mucosal subtypes compared with Western figures Overall incidence of ALM subtype >% BRAF +ve % ALM 5 % skin ckit +ve % ALM NIL skin Of the skin melanomas, BRAF +ve rate highest in nodular subtype ; 7 % (/) SSM ; 50 % (5/0)

18 Although there is marked difference in proportions of melanoma subtypes, molecular profiles do not appear to differ in the Singapore population, compared with Western data Other figures from Asia include BRAF +ve rate in ALM in Korea, 9. % Japan,. %.9 % palm/sole,.5 % subungual An outlier in local Asian figures is another report from Japan which cites a BRAF +ve rate in ALM of 5 %! (/0)? Technique related * laser capture microdissection & pyrosequencing

19 Thank you