Inclusion Criteria:

- Male or female at least 18 years of age at the time of signing the informed consent
form;

- Capable of giving written informed consent, which includes compliance with the
requirements and restrictions listed in the consent form;

- Body weight >= 45 kg and a body mass index (BMI) >/= 19 kg/m2 and (inclusive);

- Able to swallow and retain oral medication;

- BRAF mutation-positive tumor (V600 E/K mutation) as determined via relevant genetic
testing;

- Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 [Oken, 1982];
NOTE: Subjects with an ECOG performance status of 2 may be eligible with the
approval of the GSK Medical Monitor

- Women of child-bearing potential and men with reproductive potential must be willing
to practice acceptable methods of birth control. Additionally, women of childbearing
potential must have a negative serum pregnancy test within 14 days prior to the first
dose of study treatment;

- Must have adequate organ function as defined by the following values:

- Absolute neutrophil count (ANC) >/=1.2 x 10^9/L

- Hemoglobin >/=9 g/dL

- Platelets >/=100 x 10^9/L

- Serum bilirubin
- Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) x ULN if liver metastases are present (with approval of GSK medical monitor)

- Serum creatinine /= 60 mL/min

- Prothrombin time (PT)/International normalized ratio (INR) and partial thromboplastin
time (PTT)
- Left ventricular ejection fraction
Exclusion Criteria:

- Currently receiving cancer therapy (e.g., chemotherapy with delayed toxicity,
extensive radiation therapy, immunotherapy, biologic therapy, or major surgery)
within the last three weeks; chemotherapy regimens without delayed toxicity within
the last two weeks; or use of an investigational anti-cancer drug within four weeks
preceding the first dose of GSK2118436;

- Current use of a prohibited medication or requires any of these medications during
the study;

- Consumption of red wine, Seville oranges, grapefruit or grapefruit juice from seven
days prior to the first dose of study medication;

- Current use of therapeutic warfarin (note: low molecular weight heparin and
prophylactic low-dose warfarin are permitted);

- History of sensitivity to heparin or heparin-induced thrombocytopenia;

- The radiation exposure from the previous three year period is over 10 millisieverts
(mSv) for subjects who have been exposed to ionizing radiation above background as a
result of their work with radiation as Category A (classified) workers or as a result
of research studies they may have been involved in. Subjects will be excluded if
exposure levels cannot be verified. Clinical (therapeutic or diagnostic) exposure
will not be included;

- An occupation which requires monitoring for radiation exposure, nuclear medicine
procedures or excessive x-rays within the past 12 months;

- Any major surgery within the last four weeks;

- Unresolved toxicity equal to or greater than National Cancer Institute Common
Terminology Criteria for Adverse Events, version 4.0 (NCI CTCAE v4.0) [NCI, 2009]
Grade 2 from previous anti-cancer therapy except alopecia;

- Presence of active gastrointestinal disease or other condition (e.g., gastrectomy,
bariatric surgery, small bowel or large bowel resection) that may interfere
significantly with the absorption of drugs. If clarification is needed as to whether
a condition will significantly affect absorption of drugs, contact the GSK medical
monitor for permission to enroll the subject;

- A history of known Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), or
Hepatitis C Virus (HCV) infection (subjects with laboratory evidence HBV clearance
may be enrolled with permission of the GSK medical monitor);

- Patients with a history of malignancy that have been definitively treated can be
enrolled with approval of the GSK medical monitor;

- Subjects with brain metastases are excluded if their brain metastases are either:

Symptomatic Treated (surgery, radiation therapy) but not clinically and radiographically
stable one month after local therapy, or Asymptomatic and untreated but > 1 cm in the
longest dimension Patients with small ( brain metastases that do not need immediate local therapy can be enrolled with the
approval of the GSK medical monitor. Subjects on a stable dose of corticosteroids for more
than one month, or those who have been off corticosteroids for at least two weeks can be
enrolled with approval of the GSK medical monitor. Subjects must also be off of
enzyme-inducing anticonvulsants for more than four weeks;

- History of alcohol or drug abuse within six months prior to screening;

- Corrected QT (QTc) interval >/= 480 msecs;

- History of acute coronary syndromes (including unstable angina), coronary
angioplasty, or stenting within the past 24 weeks;

- Class II, III, or IV heart failure as defined by the New York Heart Association
(NYHA) functional classification system; abnormal cardiac valve morphology documented
by echocardiogram (subjects with minimal abnormalities [ie, mild
regurgitation/stenosis] can be entered on study with approval from the GSK medical
monitor); or history of known cardiac arrhythmias (except sinus arrhythmias) within
the past 24 weeks;

- Known immediate or delayed hypersensitivity reaction or idiosyncrasy to drugs
chemically related to the study drugs, or excipients (note: to date there are no
known drugs chemically related to GSK2118436 which are approved by the Food and Drug
Administration);

- Uncontrolled medical conditions (e.g., diabetes mellitus, hypertension),
psychological, familial, sociological, or geographical conditions that do not permit
compliance with the protocol; or unwillingness or inability to follow the procedures
required in the protocol;

- Subjects with known glucose 6 phosphate dehydrogenase (G6PD) deficiency;

- The subject has participated in a clinical trial and has received an investigational
product within the following time period prior to the first dosing day in the current
study: 30 days, five half-lives or twice the duration of the biological effect of the
investigational product (whichever is longer);

- Where participation in the study would result in donation of blood or blood products
in excess of 500 mL within a 56 day period;

- Pregnant females as determined by positive pregnancy test at screening or prior to
dosing;

- Lactating females who are actively breast feeding;

- Subject is mentally or legally incapacitated;