This study will determine the maximum tolerated dose and the dose-limiting toxicities of RO4987655 in patients with advanced and/or metastatic solid tumors. In the first part of the study, groups of patients will be sequentially enrolled to receive ascending oral doses of RO4987655 daily for 28 days. The starting dose of 1mg daily will be escalated in subsequent groups of patients after a successful assessment of the safety and tolerability of the previous dose. In Part 2 of the study, patients with metastatic or advanced malignant melanoma, or any other responsive tumor type, will be randomized to receive either the maximum tolerated dose or the optimal biological dose of RO4987655 daily. The anticipated time on study treatment is until disease progression, and the target sample size is <100 individuals.

Inclusion Criteria:

• adult patients, >=18 years of age;
• advanced and/or metastatic cancer not amenable to standard therapy;
• any solid tumor type (Part 1); malignant melanoma or other responsive tumor type (Part 2);
• measurable and/or evaluable disease (Part 1); >=1 measurable lesion (Part 2);
• ECOG performance status 0-2.

Exclusion Criteria:

• prior chemotherapy, radiotherapy or immunotherapy within 28 days of first receipt of study drug;
• prior corticosteroids as anti-cancer therapy within 14 days of first receipt of study drug;
• active CNS lesions;
• acute or chronic infection.