A Rollover Study to Provide Continued Treatment With GSK2118436 to Subjects With BRAF Mutation-Positive Tumors

Inclusion Criteria: * Has provided signed written informed consent for this study * Has demonstrated compliance with study drug(s), treatment visit schedules, and the requirements and restrictions listed in the consent form * Is currently participating in a GSK-sponsored study of GSK2118436 * Currently has no evidence of progressive disease, as determined by the investigator, following previous treatment with GSK2118436 (either as monotherapy or as part of a combination treatment regimen) * For Cohort C only: Subjects must have a calcium phosphate product (CPP) of \<4.4 mmol\^2/L\^2 (55 mg\^2/dL\^2) if they are to continue treatment with GSK1120212 * Continued ability to swallow and retain orally administered study drug(s) and does not have any clinically significant GI abnormalities that may alter absorption such as malabsorption syndrome or major resection of the stomach or bowels * Women of childbearing potential and men with reproductive potential must be willing to continue practicing acceptable methods of birth control during the study NOTE: Oral contraceptives are not reliable due to potential drug-drug interaction with GSK2118436 * Women of childbearing potential must have a negative serum pregnancy test at the time of transition to this study and before the first dose of study treatment * French subjects: In France, a subject will be eligible for inclusion in this study only if either affiliated to or a beneficiary of a social security category Exclusion Criteria: * Permanent discontinuation of GSK2118436 in the parent study due to toxicity or disease progression * Local access to commercially available GSK2118436 * Currently receiving treatment with any prohibited medication(s) * Any unresolved toxicity \> Grade 2 (National Cancer Institute-Common Toxicity Criteria for Adverse Events \[NCI-CTCAE\], version 4.0) from parent study treatment, except for alopecia, will need to be approved by the GSK Medical Monitor * Uncontrolled diabetes, hypertension or other medical conditions at the time of transition to this study that may interfere with assessment of toxicity * Presence of rheumatoid arthritis * Corrected QT (QTc) interval \>/= 480 msec at the time of transition to this study * Left ventricular ejection fraction (LVEF) \</= institutional lower limit of normal (LLN) by ECHO at the time of transition to this study * Class II, III, or IV heart failure as defined by the New York Heart Association (NYHA) functional classification system at the time of transition to this study * Pregnant or lactating female * Any serious and/or unstable pre-existing medical, psychiatric disorder or other conditions at the time of transition to this study that could interfere with subject's safety, obtaining informed consent or compliance to the study procedures, in the opinion of the investigator or GSK Medical Monitor