Absolutely! Although tumor necrosis may be associated with mild to moderate leukocytosis, another explanation for a rise in WBC count (particularly when “leukemoid” like) in patients with cancer may be related to granulocyte colony-stimulating factor (G-CSF) production by the neoplasm itself.  

In vivo production of G-CSF by bladder cancer was reported over 25 years ago in a patient with marked leukocytosis (>100,000)¹.  Subsequently, numerous G-CSF-producing tumors have been reported, including those associated with the genitourinary  tract (eg, bladder, ureter, prostate), lung, gynecological organs, gallbladder, stomach, esophagus, small intestine, pancreas, mesothelioma, thyroid, and myeloma².

 In most cases, G-CSF-producing tumors are advanced with very poor prognosis ².  Although the mechanism underlying a link between G-CSF production and tumor progression is unclear, a direct action on GCSF receptors of tumor cells, formation of more aggressive cancer cells,  and changes in  the function of T-cells and endothelial cells that may enhance tumor growth have been postulated².

References

1. Ito N, Matsuda T, Kakehi Y, et al. Bladder cancer producing granulocyte colony-stimulating factor. N Engl J Med 1990;323:1709-10. http://www.nejm.org/doi/pdf/10.1056/NEJM199012133232418
2. Yamano T, Moril E, Ikeda J-I, Aozasa K. Granulocyte colony-stimulating factor production and rapid progression of gastric cancer after histological change in the tumor. Jpn J Clin Oncol 2007;37:793-796. https://academic.oup.com/jjco/article/37/10/793/831502