Sporadic mutations and expression analysis of spleen tyrosine kinase gene in breast cancer: a preliminary report

Spleen tyrosine kinase (Syk) is an intracellular receptor protein kinase involved in cell proliferation, differentiation and phagocytosis. Syk expression has been reported in cell lines of epithelial origin. The strong expression of Syk in mammary gland prompted research into its potential role in mammary carcinogenesis. Fresh Biopsy samples were collected from different hospitals of Pakistan. Single stranded conformational polymorphism and Semi quantitative reverse transcriptase polymerase chain reaction was used to investigate somatic mutations and expression alterations in twenty five breast cancer tumor tissues along with their adjacent normal control tissue. Statistical analysis was performed to explore Syk association with breast cancer risk. In the present study, DNA from tumor tissue was analyzed and mutations in the coding sequence and intronic sequence spanning the exonic region of the Syk gene were identified. Sequence analysis revealed two missense: g61096G>A, g65967G>A, one frame shift: g87413insA and one silent mutation g42841G>A in exonic region while nucleotide variations were also observed in intronic region including one splice site mutation. These mutations in Syk are first time being reported in breast cancer. In addition, this study also revealed that Syk mRNA expression was markedly reduced in tissues of breast cancer compared to their adjacent normal control tissue.