The investigators hypothesize that genetic variations between different individuals and ethnic groups may account for inter-individual and inter-ethnic differences in treatment response and toxicities to anti-cancer therapy. The understanding of the contribution of these genetic variations may help to individualize therapy to optimize treatment outcomes and reduce toxicities. Patients will be recruited from the National University Hospital Cancer Centre. Any individual aged 18 or above who has been diagnosed with cancer is eligible. 20 ml of blood will be collected from each subject for DNA extraction and pharmacogenetics analysis. At the time of recruitment, demographic characteristics, cancer history, and past and present cancer treatment history of the study subject will be collected. The patients' progress will be followed up periodically (approximately every 6 months) through the medical records, and subsequent cancer treatments, progression of cancer, and survival outcome will be updated. Follow-up will occur until death. Important treatment information that will be collected include the drug regimen, drug doses, intent of treatment, aematologic and non-haematologic toxicities, and hospitalization episodes that may be related to treatment. Known functional single nucleotide polymorphisms (SNPs) of drug metabolizing enzymes, transporters and targets of different anti-cancer agents will be characterized. More comprehensive genotyping will be carried out in 'outliers' who experience exceptional toxicity or biological response to identify novel functional SNPs using high throughput sequencing techniques. Correlation will be made between genotype and treatment-related outcomes (tumor response, progression-free survival) and toxicities. For selected patients, lymphoblastoid transformation will be carried out to maintain an infinite supply of DNA.