GRN and thyroid gland papillary carcinoma: Progranulin expression levels were significantly upregulated in non-invasive low-grade papillary carcinomas (Ta) compared to benign tissues and enhanced in both non-invasive high-grade papillary carcinomas (Ta) and high-grade carcinoma tissues compared to benign tissues, while in non-invasive carcinoma in situ (Tis) progranulin expression was at levels similar to benign tissues (41).