ABSTRACT
Objective@#RET/PTC gene rearrangement can lead to aberrant activation of tyrosine kinase receptors, which is a common mutation in papillary thyroid carcinoma (PTC). This study focuses on the association of RET/PTC rearrangements with PTC clinical factors.@*Methods@#From January 2011 to December 2013, a total of 114 patients with PTC were enrolled in this study. Clinicopathological parameters, lifestyle, and thyroid hormone levels were collected. RET/PTC rearrangements were detected by TaqMan PCR and verified by Sanger sequencing.Data were analyzed with SPSS software, including chi-square test, Fisher′s exact test, Mann-Whitney U test, Student′s t-test, and Logistic regression.@*Results@#RET/PTC rearrangements were not found in all paracancerous normal thyroid tissues, and were detected in 23.68% (27/114) of PTC. Further analysis revealed no correlation between RET/PTC rearrangement and thyroid function, clinicopathologic parameters, and lifestyle in the total PTC group or in the subgroup of patients with concomitant diseases (including Hashimoto′s thyroiditis and nodular goiter). But in the subgroup of PTC without concomitant disease, RET/PTC rearrangement was associated with tumor multifocal (P=0.018), and RET/PTC-positive PTC patients had an increased risk of tumor multifocal (OR=5.57, 95% CI 1.39-22.33). It was also found that RET/PTC rearrangement was associated with an abnormal increase in TSH level of one month after surgery (P= 0.037).@*Conclusion@#Nodular goiter and Hashimoto ′s thyroiditis may be a confounding factor in PTC. RET/PTC rearrangement may play an important role in the occurrence of thyroid carcinoma multifocal after exclusion of this confounding factor.
ABSTRACT
AIM To characterize the primary structure of recombinant L-asparaginase II product. METHODS The molecular weight of the protein was measured by pneumatically-assisted electrospray ionization mass spectrometry with flow injection mode. Subsequently, tryptic peptide mapping was performed by high performance liquid chromatography on a C8 column with tandem UV and MS detection. An easy-to-use and simple denaturation process with trichloroacetic acid was conducted prior to tryptic digest so as to release the digest resistance from the protein structure. The amino acid sequences of the tryptic peptides were elucidated based on their in-source collision-induced dissociation spectra. RESULTS The measured molecular mass was different from the theoretical value. Three amino acid variations were unambiguously detected along the peptide backbone derived from the gene-encoding sequence. CONCLUSION This paper revealed that LC/ESI/MS had provided a promising and robust technique in primary structure analysis and quality control of DNA-derived recombinant protein pharmaceuticals.