An unusual false-positive uptake of radioiodine caused by pulmonary vasculature: The usefulness of SPECT/CT

There are numerous conditions that may cause false-positive findings on iodine scintigraphy, such as vascular structure, mediastinum, bronchiectasis, cystic lesions and mature cystic teratoma; however, many of their mechanisms remain to be elucidated. Single photon emission tomography/computed tomography (SPECT/CT) imaging can be conducive to avoiding potential pitfalls. In addition, the nuclear physicians have to bear in mind that iodine-131 (¹³¹I) uptake in pulmonary vasculature can be a possible cause of false-positive uptake when they interpret ¹³¹I whole body scan (WBS).

Exosomes increased angiogenesis in papillary thyroid cancer microenvironment

Tumour-derived exosomes under hypoxic conditions contain informative miRNAs involved in the interaction of cancer and para-carcinoma cells, thus contributing to tissue remodelling of the tumour microenvironment (TME). Exosomes isolated from hypoxic papillary thyroid cancer cells, BCPAP cells and KTC-1 cells enhanced the angiogenesis of human umbilical vein endothelial cells (HUVECs) compared with exosomes isolated from normal thyroid follicular cell line (Nthy-ori-3-1), normoxic BCPAP or KTC-1 cells both in vitro and in vivo. miR-21-5p was significantly upregulated in exosomes from papillary thyroid cancer BCPAP cells under hypoxic conditions, while the exosomes isolated from hypoxic BCPAP cells with knockdown of miR-21-5p attenuated the promoting effect of angiogenesis. In addition, our experiment revealed that miR-21-5p directly targeted and suppressed TGFBI and COL4A1, thereby increasing endothelial tube formation. Furthermore, elevated levels of exosomal miR-21-5p are found in the sera of papillary thyroid cancer patients, which promote the angiogenesis of HUVECs. Taken together, our study reveals the cell interaction between hypoxic papillary thyroid cancer cells and endothelial cells, elucidating a new mechanism by which hypoxic papillary thyroid cancer cells increase angiogenesis via exosomal miR-21-5p/TGFBI and miR-21-5p/COL4A1 regulatory pathway.

Angiogenic and lymphangiogenic profiles in histological variants of papillary thyroid carcinoma

INTRODUCTION

Papillary thyroid carcinoma (PTC) is a well‑differentiated tumor that occurs in several histological variants whose biological behaviors remain unclear. Angiogenesis and lymphangiogenesis are critical processes that enable tumor progression.

OBJECTIVES

The aim of this study was to evaluate the angiogenic and lymphangiogenic phenotypes of PTC, considering the differences between histological variants.

PATIENTS AND METHODS

Angiogenic and lymphangiogenic profiles were analyzed by determining microvascular density (MVD) and lymphatic vessel density (LVD) in 73 cases of PTC, using immunohistochemistry. To assess the biological markers involved in blood and lymph vessel formation, the expression of vascular endothelial growth factor (VEGF), cyclooxygenase 2 (COX‑2), and p27kip1 (p27) was determined.

RESULTS

MVD was significantly higher in patients with high‑risk PTC and in those with local extrathyroidal and vascular invasion. Positive VEGF expression was strongly associated with high MVD and age‑related tumor enlargement. The presence of lymph vessel invasion was associated with the expression of either VEGF or COX‑2. The analysis of angiogenesis and lymphangiogenesis in different histological variants of PTC revealed elevated LVD rather than MVD in the follicular variant of PTC (FV‑PTC).Lower MVD was observed in FV‑PTC relative to the classic variant of PTC (CV‑PTC). The frequency of VEGF‑positive tumors was higher in CV‑PTC than in FV‑PTC. A significant association between COX‑2 and p27 expression was observed in FV‑PTC but not in CV‑PTC.

CONCLUSIONS

These results suggest that VEGF, COX‑2, and p27 may be important biological markers that determine the angiogenic and lymphangiogenic potentials of PTC, particularly between the follicular and classic variants.