Figure 1: (A) Overlay of average mass spectra for protein obtained from primary breast (shown in red) and lung adenocarcinomas (shown in green). (B) A principal component analysis plot for 10 primary breast cancer samples (shown in red) and 18 primary lung adenocarcinoma samples (shown in green), which graphically represents Euclidean distances among samples. Each sphere represents a single sample, and samples whose protein expression profiles are very similar are shown clustered together. A breast cancer metastasis to the lung (shown in blue) is located close to primary breast cancers.