Neutrophilic leucocytosis induced by granulocyte colony-stimulating factor and interleukin-6 in canine primary lung adenocarcinoma.

Background: Neutrophilic leucocytosis as a paraneoplastic syndrome may occur in dogs with lymphoma, renal carcinoma, rectal polyps and metastatic fibrosarcoma. However, the information on canine lung adenocarcinoma with neutrophilic leucocytosis is lacking.

Objective: This study aimed to describe the clinical features and cytokine profiles of canine patients with primary lung adenocarcinoma and neutrophilic leucocytosis.

Methods: Two dogs (cases #1 and #2), each with a solitary lung adenocarcinoma, were included. Both cases had leucocytosis and underwent lung lobectomy. The resected tumours were analysed for the expression of granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-6 (IL6) by quantitative real-time PCR compared with normal lung tissues.

Results: At the initial examination, neither patient had any clinical signs or fever. White blood cell count (WBC) was 58,300/μl and 32,900/μl in cases #1 and #2, respectively. The gene expression of G-CSF increased 6.7-and 19.7-fold in cases #1 and #2, respectively. The gene expression of IL6 markedly increased (30-fold) in case #1, whereas it increased slightly (1.9-fold) in case #2. On the other hand, that of GM-CSF was slightly changed in both cases. The WBC count postoperatively decreased to within the normal range in both cases. The postoperative survival times were 347 and 118 days in cases #1 and #2, respectively.

Conclusions: This study describes G-CSF and IL6 producing lung adenocarcinoma associated with neutrophilic leucocytosis in dogs. Canine patients with pulmonary adenocarcinomas that have elevated G-CSF and IL6 levels may have a guarded prognosis. Further investigations are needed to clarify the prognosis of canine cytokine-producing lung adenocarcinoma.