Changes in sialyl glycosylation on the surface of lung adenocarcinoma cells regulates their interaction with inflammatory monocytes. A subpopulation of tumor cells differentially express specific glycosyltransferases to truncate cell surface glycans. Gal-3 expressed at the surface of monocytes preferentially binds to truncated glycans. The Gal-3 mediated interaction between monocytes and tumor cells is observed during liver colonization, but may also occur at different steps of cancer progression to support lung tumor expansion, intravasation, survival in circulation, extravasation, and secondary outgrowth. Analogous glycoprotein modifications may be required for lung cancer metastasis to other relevant organs, such as the brain.