The relationship between helper T cell subtype expression and clinicopathologic manifestation of papillary thyroid carcinoma with lymphocytic thyroiditis

Abstract

In South Korea, the incidence of thyroid cancer is one of highly occurring cancer. Out of thyroid cancers, papillary thyroid carcinoma (PTC) is the highest. PTCs were frequently accompanied by lymphocytic thyroiditis (LT). Some articles reported Hashimoto’s thyroiditis (HT; extreme form of LT) increased occurrence of PTC. In contrast, others reported LT had an anti-tumor activity, which leaded to a good prognosis.Concerning two conflicting results, this study was performed to unravel how LT was operated in cancer immunity.Two subtypes of helper T cell (Th) cytokines were used; Th1 (IFN-γ, TNF-α, IL-2) and Th2 (IL-4, IL-10, IL-1β). The cytokine levels were measured by quantitative RT-PCR method using non-tumor tissue. Because most PTC cases represented microcarcinomas, p27 immunohistochemical marker was used as a surrogate marker for lymph nodal metastasis.This study revealed that most PTCs have mixed Th1 (IFN-γ, TNF-α, IL-2) and Th2 (IL-4, IL-10, & IL-1β) immunity. Cytokines were always expressed more in the cases with LT than those without LT. When statistically analysis was confined to the PTC cases with LT, the cases with lower levels of cytokines had a tendency to be related to low grade expression of p27. Considering under-expression of p27 as being closely associated with lymph nodal metastasis, this result implicated that lower levels of cytokines were frequently found in the cases with nodal metastasis. In other words, high expression of cytokines might play a role in inhibiting lymph nodal metastasis. The cases with extrathyroidal tumor extension had a tendency to show the higher levels of cytokine expression than those with intrathyroidal tumor confinement. Although this result could not determine whether it implicated an anticancer effect or not, there was a tendency to the increased level of cytokines in the cases with extrathyroidal tumor extension.This result implicated that mixed Th1 and Th2 cytokines might have an anticancer effect, only in terms of lymph nodal metastasis