Clinical association of CXCR4 in primary tumor of papillary thyroid cancer and response to iodine-131 treatment

Object Papillary thyroid cancer (PTC) has an excellent prognosis. However, patients with such, if refract to radioiodine treatment, increase recurrent and mortality rates. Tumor aggressiveness in primary tumor of PTC expresses CXCR4 chemokine receptor. Thus, CXCR4 expression of the tumor may predict response to radioiodine treatment. Materials and methods Retrospective review of seventy-four PTC patients, treated with total/near-total thyroidectomy and radioiodine treatment at King Chulalongkorn Memorial Hospital from January 2007 to 2013, were classified as non-radioiodine-refractory (non-RAIR) or RAIR treatment response. All histopathologic diagnoses were reviewed and paraffin blocks were retrieved for CXCR4 immunostaining, determined by automated digital imaging analysis for intensity and extension. The scores were compared between primary tumour and adjacent normal thyroid tissue as well as between the tissue of non-RAIR and that of RAIR. Factors determining type of RAI response were analyzed. Results CXCR4 immunostaining scores of PTC is significantly higher than normal thyroid [2.03 (0.52) and 1.48 (0.75)] [mean (SD)] ( P = 0.0001). CXCR4 immunostaining scores in RAIR are potentially higher than non-RAIR [1.95 (0.54) and 2.13 (0.47) ( P = 0.149)]. Odds ratio of CXCR4 immunostaining score for predicting RAIR treatment is 1.99 ( P = 0.150). CXCR4 immunostaining scores positively associate with tumor size ( R = 0.298, P = 0.01); whereas no significant association with other clinicopathologic factors. Conclusion Our data support the notion that CXCR4 are significantly expressed in PTC tumor over normal thyroid tissues. However, there is no clinical association with radioiodine treatment response.