Growth Factor Receptors
Certain growth factors can influence normal cell differentiation, and constitutive activation of growth-promoting pathways in cancer cells can also modulate the cell phenotype.[25] One such growth factor is gastrin-releasing peptide receptor (GRPR), which plays a role in human carcinogenesis by stimulating cell proliferation,[26] and has been identified in both SCLC and NSCLC.[27,28] In a study by Shriver et al., GRPR mRNA expression was detected more frequently in female nonsmokers than in male nonsmokers (55 and 0%, respectively).[29] Among smokers with lower levels of tobacco exposure (< 25 pack-years), a much higher rate of expression of GRPR mRNA was observed for women (75%) compared with men (20%).[29] The investigators also analyzed the pack-years of tobacco exposure at the time of diagnosis of lung cancer and noted that female subjects developed lung cancer with significantly less tobacco exposure than did the males (41 and 59.9 pack-years, respectively; p = 0.032). Almost all the non-smokers diagnosed with lung cancer in this study were women, and five out of six non-smoking women with lung cancer had increased GRPR expression.[29]
Some studies have shown that a small subset of NSCLCs overexpress Her2-neu, one of four receptor-type tyrosine kinases that belongs to the Erb-B class of receptors that mediates cell growth and survival. It is reported that Her2-neu overexpression occurs in 4–27% of NSCLCs.[30] Her2-neu is more commonly expressed in adenocarcinoma,[31] the most common subtype in women and overexpression of the growth factor has been reported to be associated with poorer prognosis and survival.[32]
Expert Rev Resp Med. 2009;3(6):627-634. © 2009
Cite this: Lung Cancer in Women: The Differences in Epidemiology, Biology and Treatment Outcomes - Medscape - Dec 01, 2009.
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