HER2 status predicts the presence of circulating tumor cells in patients with operable breast cancer.
BACKGROUND
Circulating tumor cells (CTCs) correlate with worse prognosis in patients with metastatic breast cancer, but there are little data on CTCs in operable patients. We hypothesized that primary tumor characteristics would predict the likelihood of identifying CTCs in patients with operable breast cancer.


METHODS
Clinical and pathological data from 92 patients with operable breast cancer were collected. The CellSearch system was used to detect CTCs in 30 ml of peripheral blood. CTCs were defined as nucleated cells lacking CD45 but expressing cytokeratins 8, 18, or 19. Univariate analysis was performed to determine if the presence of any primary tumor characteristic was predictive of CTCs. As a secondary objective we evaluated if nodal or bone marrow status was predictive of CTCs.


RESULTS
Thirty-eight percent of patients (35/92) had evidence of CTCs, with a median number of 1.0 CTC per CTC positive patient (range 1-22). HER2 status was the sole primary tumor characteristic that reliably predicted the presence of CTCs (P = 0.01, risk ratio = 3.66). No significant association was found between the presence of CTCs and tumor size (T), estrogen receptor (ER) status, progesterone receptor (PR) status, grade, histologic type, degree of nodal involvement (N), lymphovascular invasion (LVI) or Ki-67 proliferation. Bone marrow micrometastases were found in 17/64 (26.6%) of the patients but did not correlate with the presence of CTCs.


CONCLUSIONS
HER2 status was the only primary tumor characteristic that correlated with the presence of CTCs. Long-term follow-up will be required to determine the significance of CTCs in operable breast cancer.
Lang
Julie E
JE
Department of Surgical Oncology, MD Anderson Cancer Center, Advanced Research Center for Microscopic Disease, The University of Texas, , Houston, TX 77030, USA.
Mosalpuria
Kailash
K
Cristofanilli
Massimo
M
Krishnamurthy
Savitri
S
Reuben
James
J
Singh
Balraj
B
Bedrosian
Isabelle
I
Meric-Bernstam
Funda
F
Lucci
Anthony
A
D001853:Bone Marrow / Q000473:pathology; D001856:Bone Marrow Examination; D019046:Bone Marrow Neoplasms / Q000235:genetics* / Q000556:secondary; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D005260:Female; D018734:Genes, erbB-2; D006801:Humans; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D011446:Prospective Studies