The invention discloses nearly 443 novel phosphorylation sites identified in signal transduction proteins and pathways underlying human carcinoma, and provides phosphorylation-site specific antibodies and heavy-isotope labeled peptides (AQUA peptides) for the selective detection and quantification of these phosphorylated sites/proteins, as well as methods of using the reagents for such purpose. Among the phosphorylation sites identified are sites occurring in the following protein types: Protein kinases (including Serine/Threonine dual specificity, and Tyrosine kinases), Adaptor/Scaffold proteins, Transcription factors, Phospoatases, Tumor supressors, Ubiquitin conjugating system proteins, Translation initiation complex proteins, RNA binding proteins, Apoptosis proteins, Adhesion proteins, G protein regulators/GTPase activating protein/Guanine nucleotide exchange factor proteins, and DNA binding/replication/repair proteins, as well as other protein types.