Cluster analysis of lung adenocarcinoma samples. (A) Eleven cancer and 11 normal tissue samples were used as a training set to identify a list of 55 CpG sites that are differentially methylated in cancer versus normal tissues with high confidence level (adjusted P-value < 0.001) and significant change in absolute methylation level (|Δβ| > 0.15). Cancer sample G12029 was mistakenly coclustered with normal samples. (B) The selected 55 CpG sites were used for classification of an independent test sample set of 12 lung adenocarcinoma and 12 normal tissue samples, collected from a different institute. All the normal and cancer samples were separated into two distinguished groups with a single error—cancer sample D12162 was coclustered with normal samples. Normal samples are underlined in green, cancer in red. The asterisks indicate misclassified samples.