Cutaneous melanoma is the most aggressive malignancy in skin cancers. Cutaneous melanoma is a rare disease in Taiwan with an incidence rate of around 1/100,000. Acral lentiginous melanoma is the most common subtype and comprises more than half of cutaneous melanoma in Asia including Taiwan but only 1% in Caucasians. In addition, mucosal melanoma accounts for more than 20% of malignancy melanoma in Taiwan but only 1% in Caucasians. Acral and mucosal melanomas have distinct epidemiological, clinical, pathological and genetic features from non-acral melanoma which is commonly seen in Western countries. Comparing with melanoma in Caucasians, Asian melanoma has higher recurrence rate after primary surgery, lower response rate to immunotherapy, and shorter progression-free survival for immunotherapy and targeted therapy leading generally poor survival outcomes regardless stage.

Most melanoma patients present with locally advanced or metastatic disease at diagnosis reflecting the aggressive disease nature of melanoma in Taiwan. Currently, surgical resection of primary tumor and lymph node dissection are the main treatment for patients with locally advanced melanoma. Adjuvant therapy should be considered for stage III melanoma. Unfortunately, most patients recur after above aggressive treatment. Systemic treatment including targeted therapy, immunotherapy and chemotherapy is the main for unresectable or metastatic melanoma. The prognosis of these patients remains poor with a median survival time around a year. Therefore, a better understanding of this deadly disease is crucial and finding better therapeutic strategies for these patients and stratifying patients with suitable treatment are urgent.

Inclusion Criteria:

1. Age > 18 years old
2. Pathologically confirmed melanoma. (Patients with additional malignancies requiring treatment or follow-up are allowed. Only treatment for melanoma should be recorded).
3. ECOG performance status < 3
4. Cohort 1(early acral melanoma): melanoma, stage I/II; Cohort 2 (locally advanced acral melanoma): melanoma, stage III, resectable; and Cohort 3 (advanced): unresectable / metastatic melanoma, stage III/IV or recurrent melanoma (unresectable). Staging is based on AJCC Cancer Staging System 8th edition). The patients with advanced melanoma with available comprehensive NGS report are included in cohort 4.
5. Willingness to provide archival or newly obtained tumor tissues for this study proposal
6. Life expectancy more than 3 months -
7. Patients fully understand the protocol with the willingness to have regular follow-up

Exclusion Criteria:

1. Inability to cooperate by providing a complete medical history
2. No available tumor tissues for genetic testing (archived tissue sampling more than 5 years from screening date)
3. Undesirable compliance (Mental status is not fit for further treatment or data collection.)

Cohort 1(early acral melanoma): melanoma, stage I/II; Cohort 2 (locally advanced acral melanoma): melanoma, stage III, resectable; and Cohort 3 (advanced): unresectable / metastatic melanoma, stage III/IV or recurrent melanoma (unresectable). Staging is based on AJCC Cancer Staging System 8th edition). The patients with advanced melanoma with available comprehensive NGS report are included in cohort 4.