PDPR Gene Variants Predisposing to Papillary Thyroid Cancer

Background: Papillary thyroid cancer (PTC) is the predominant subtype of thyroid cancer (THCA), and it can cluster in families with an autosomal dominant (AD) inheritance pattern. The aim of this study was to identify novel genes and mechanisms underlying PTC susceptibility. Methods: Our previous investigation of 17 AD PTC families led us to conduct a deeper analysis on one family (Family Q) with whole-genome sequencing data from 3 PTC-affected individuals. In addition, 323 sporadic THCA cases from Avatar data and 12 familial adenomatous polyposis (FAP) individuals with secondary THCA were screened for pyruvate dehydrogenase phosphatase regulatory (PDPR) variants. CRISPR-Cas9 was used to create PDPR-deficient THCA (TPC1) and transformed normal thyroid cell lines (N-Thyori3-1) to study the metabolic consequences of PDPR loss. Results: We found truncating PDPR splice donor variants (NM_017990.4:c.361 + 1G>C) in all affected PTC Family Q members, and another PDPR splice donor variant (NM_017990.4:c.443 + 1G>C) in a sporadic PTC case. In addition, an ultra-rare missense variant was found in an FAP-PTC patient. The PDPR-deficient cells presented with elevated phosphorylation of pyruvate dehydrogenase and altered glucose metabolism, implying that PDPR plays an essential part in regulating glucose metabolism in thyroid cells. Conclusions: Our finding of novel truncating germline variants in PDPR in Family Q and additional cohorts suggests a role for PDPR loss in PTC predisposition. Also, somatic and RNA sequencing from the thyroid carcinoma (Firehouse Legacy) data showed that PDPR gene expression is much lower in THCA tumor tissue compared with matching normal tissue. Thus, PDPR appears to have a loss of function effect on THCA tumorigenesis.

Physiological characteristics of elite synchronized swimmers

The physiological characteristics of 32 elite Canadian synchronized swimmers were studied. The variables examined included aerobic power (VO2 max), anaerobic power measured by a maximal 30 second effort on a bicycle ergometer (AN30) and pulmonary function including forced vital capacity (FVC) and forced expiratory volume in one second (FEV 1.0). As a group, they were superior to non-athletic (untrained) women in VO2 max, with a mean of 44.4 ml . kg-1 . mon-1 or 2.39 l . min-1 but lower than competitive women swimmers of similar age. FVC and FEV 1.0 values were also higher than non-athletes and lower than competitive swimmers. AN30 was unremarkable, being identical to that of non-athletes. Comparisons were made between junior and senior competitors and between the 2 senior teams that made up the Canadian national team. Correlations between the athletes' performance scores in the 1977 Canadian national championships and VO2 max, AN30, FVC amd FEV 1.0 failed to yield any significant relationships. However, VO2 max in ml . kg-1 . min-1 related to solo performance scores was very close to the accepted level of significance (r = .41, p = 06). Precision techniques and skills are undoubtedly of major importance in this sport. However, a level of aerobic power sufficient to prevent fatigue during a performance and to allow long hours of training on technique would be prudent.