CD117: A novel ancillary marker for papillary thyroid carcinoma in fine‐needle aspiration biopsies

Abstract

BACKGROUND: c-KIT/CD117 down-regulation has been described in papillary thyroid carcinoma (PTC). In this study, the authors investigated CD117 as an ancillary immunocytochemical test for PTC in fine-needle aspiration biopsy (FNAB). METHODS:The expression of CD117 was assessed in cytologic samples of histologically confirmed classic PTC (n 5 35) and in a control group of benign thyroid nodules (BTNs) (n 5 30) using immunocytochemistry. The corresponding PTCs and BTNs from surgical resection specimens also were evaluated immunohistochemically for CD117. The expression of CD117 was assessed semiquantitatively using a scoring system from 0 to 5 that combined the proportion and the intensity of staining. RESULTS: The difference in immunoreactivity for CD117 between PTC and BTNs was highly significant both in FNAB samples and in the corresponding histology samples (P <.0001). On cytology, most PTCs (74%; n 5 26) lacked immunoreactivity for CD117, and 9 samples (26%) had faint reactivity in <2% of tumor cells (score, 0). In contrast, all BTNs (100%; n 5 30) were positive for CD117, and at least 50% of the cells (score, 2-4) were positive in 79% (n 5 24) of BTNs.Results with corresponding histology were similar to the cytology results; most PTCs (89%; n 5 31) lacked immunoreactivity for CD117, and 4 samples (11%) had faint reactivity in <2% of tumor cells. In contrast, all BTNs (n 5 30) were variably positive for CD117 (score, 2-4). Normal follicular epithelium also was positive for CD117 (score, 2-4). CONCLUSIONS: CD117 is expressed in both normal follicular epithelium and in BTNs. In contrast, expression of CD117 is absent or weak in PTC.These results suggest that CD117 may be useful as an ancillary marker for PTC. Cancer (Cancer Cytopathol) 2014;122:596-603.

Mutant-specific BRAF and CD117 immunocytochemistry potentially facilitate risk stratification for papillary thyroid carcinoma in fine-needle aspiration biopsy specimens

“…On the other hand, CD117 expression level also showed nice performance characteristics in a sample pool with various cytological diagnosis (sensitivity = 92.48 %, specificity = 89.36 %, AUC=0.931, p<0.001) when used alone. Our results were in consistency with previous studies [8,11].…”

“…Pusztaszeri et al revealed a clear divergence in CD117 expression level between PTC and benign thyroid nodules, where benign thyroid nodules and normal thyroid follicular tissue expressed a high level of CD117, while PTC expressed no or low level of CD117 protein, resulting in a 100 % sensitivity and specificity for a mono parameter [8]. However, their study only enrolled cytologically benign and PTC cases and the validity on indeterminate or suspicious cases remained unrevealed.…”

“…Investigation using CD117 expression as an ancillary marker for diagnosing PTC in FNA specimens yielded promising results [8].…”

Loss of c-KIT expression in thyroid cancer cells

“…More recently, other studies have been published showing a decreased c-KIT expression in PTC compared to normal thyroid tissues [27, 28]. Several mechanisms have been described that can mediate the downregulation of c-KIT, including dysregulated expression of specific microRNAs [29] (miR-146b, miR-221, and miR-222) and promoter hypermethylation [12]; however, there are no studies that investigate this events in thyroid tumors.…”

TROP‐2 expression in papillary thyroid carcinoma

“…A total of 331 TMA were selected and included; classic PTC (60), FVPTC (48), follicular carcinoma (FC) (27), AC (14), MC (2), follicular adenoma (FA) (8) and BTN (172). Donor blocks were selected.…”