PURPOSE: The purpose of this study was to examine breast tumors and normal 
breast tissues for the expression of the glycoprotein lacritin. The mRNA and 
protein expression of lacritin has been reported to be restricted to the 
lacrimal gland.
METHODS: We investigated 37 human primary invasive breast tumors, seven breast 
cancer cell lines and 16 normal breast tissues by quantitative real-time PCR for 
lacritin expression.
RESULTS: We detected lacritin transcripts in 51% (19/37) of the primary invasive 
breast tumors, in 71% (5/7) of the breast cancer cell lines, and also in 56% 
(9/16) of the normal breast tissues. No lacritin mRNA was detectable in 
peripheral blood of healthy individuals.
CONCLUSIONS: Here we show by quantitative real-time PCR that lacritin is 
expressed in human breast tumors, breast cancer cell lines, and normal breast. 
The previously reported restricted expression pattern of lacritin is therefore 
incorrect. Lacritin transcripts were not detected in peripheral blood which 
makes lacritin a potential candidate as a breast cancer marker gene.