In the present pilot study, we examined the presence of
serglycin in lung, breast, prostate, and
colon cancer and evaluated its expression in cell lines and tissues. We found that
serglycin was expressed and constitutively secreted in culture medium in high levels in more aggressive
cancer cells. It is worth noticing that aggressive
cancer cells that harbor KRAS or EGFR mutations secreted
serglycin constitutively in elevated levels. Furthermore, we detected the transcription of an alternative splice variant of
serglycin lacking exon 2 in specific cell lines. In a limited number of tissue samples analyzed,
serglycin was detected in normal epithelium but was also expressed in higher levels in advanced grade
tumors as shown by immunohistochemistry.
Serglycin staining was diffuse, granular, and mainly cytoplasmic. In some
cancer cells
serglycin also exhibited membrane and/or nuclear immunolocalization. Interestingly, the stromal cells of the reactive
tumor stroma were positive for
serglycin, suggesting an enhanced biosynthesis for this
proteoglycan in activated tumor microenvironment. Our study investigated for first time the distribution of
serglycin in normal epithelial and cancerous lesions in most common
cancer types. The elevated levels of
serglycin in aggressive
cancer and stromal cells may suggest a key role for
serglycin in
disease progression.