The prognostic value of the human kallikrein gene 9 (KLK9) in breast cancer

George M. Yousef, Andreas Scorilas, Terukazu Nakamura, Mohamed Abd Ellatif, Riccardo Ponzone, Nicoletta Biglia, Furio Maggiorotto, Riccardo Roagna, Piero Sismondi, Eleftherios P. Diamandis

Research output: Contribution to journalArticlepeer-review


Background. Many members of the human kallikrein gene family were found to be differentially expressed in various malignancies and some of them are useful diagnostic/prognostic markers. KLK9 is a newly discovered human kallikrein gene that is expressed in several tissues including thymus, spinal cord, testis, prostate, breast, and ovary. Like other kallikreins, the KLK9 gene was found to be regulated by steroid hormones, mainly estrogens and progestins, in cancer cell lines. Experimental design. We studied the expression of KLK9 by quantitative RT-PCR in 169 breast cancer patients of different stages, grades and histological types. We also compared the relation between KLK9 expression and other clinicopathological variables and patient survival. Results. KLK9 expression is significantly higher in patients with early stage cancers (p = 0.039) and in patients with small tumor size (

Original languageEnglish
Pages (from-to)149-158
Number of pages10
JournalBreast Cancer Research and Treatment
Issue number2
Publication statusPublished - Mar 2003


  • Breast cancer
  • Cancer genes
  • Cancer predictive markers
  • Kallikreins
  • KLK9
  • Prognostic markers
  • PSA
  • Serine proteases
  • Tumor markers

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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