Eligibility Criteria:
Inclusion Criteria:
* over 19 years of age
* no history of receiving moderately or highly emetogenic chemotherapy during last 6 months, and is to receive a first course of MEC including one or more of following agents: Carboplatin, Cyclophosphamide ≤ 1,500 mg/m2, Daunorubicin, Doxorubicin \< 60 mg/m2, Epirubicin ≤ 90 mg/m2, Irinotecan, Oxaliplatin, Melphalan, Methotrexate ≥ 250 mg/m2
* ECOG performance status 0-2
* predicted life expectancy ≥ 3 months
* adequate bone marrow, kidney, and liver functionas evidenced by: ANC ≥ 1,500/mm3, platelet count ≥ 100,000/mm3, total bilirubine ≤ 2 x ULN, AST ≤ 3 x ULN, ALT ≤ 3 x ULN (for subjects with known liver metastases, total bilirubin ≤ 3 x ULN, AST ≤ 5 x ULN, ALT ≤ 5 x ULN), Creatinine ≤ 1.5 x ULN or Ccr ≥ 50 ml/min
* no episodes of nausea and vomiting during last 24 hours before enrollment
* subjects provides written informed consent
Exclusion criteria:
* subjects with uncontrolled neuro-psychiatric disease (alcohol abuse, seizure, psychosis etc) except malignant tumor
* subject is scheduled to receive highly emetogenic chemotherapeutic agents: Doxorubicin or Epirubicin + cyclophosphamide, Cisplatin ≥ 50 mg/m2, Carmustine \> 250 mg/m2, Cisplatin ≥ 50 mg/m2, Cyclophosphamide \> 1,500 mg/m2, Dacarbazine, Doxurubicine ≥ 60 mg/m2, Epirubicine \> 90 mg/m2, Ifosfamide ≥ 2 g/m2 per dose, Mechlorethamine, Streptozocin
* contraindication to the administration of palonosetron, dexamethasone, and olanzapine due to hypersensitivity or any other reasons
* subject has severe cognitive impairment
* subjects has symptomatic or uncontrolled brain metastasis or brain tumor
* female subjects of childbearing potential who dose not agree to use a proper contraceptive methods or to limit breast feeding
* subject has taken the following agents: risperidone, quetiapine, clozapine, phenothiazine, butyrophenone, 5-HT3 antagonist, bezamides, domperidone, cannabinoids, NK1 antagonist, bezodiazepines
* subject has a plan to receive other chemotherapy, abdomial radiation, surgery, or immunotherapy
* any history of arrhythmia, uncontrolled congestive heart failure, acute myocardial infarction durting last 6 months
* history of uncontrolled diabetes
* subject who has used any investigational drugs within 30 days of randomization