Dedifferentiated endometrial carcinoma is an aggressive type of endometrial cancer that contains a mix of low grade endometrioid and undifferentiated carcinoma components. We performed targeted sequencing of 8 dedifferentiated endometrial carcinomas and identified somatic frameshift/nonsense mutations in SMARCA4, a core member of the switch/sucrose non-fermenting (SWI/SNF) complex, in the undifferentiated components of 4 tumors. Immunohistochemical analysis confirmed the loss of SMARCA4 in the undifferentiated component of these 4 SMARCA4-mutated cases while the corresponding low grade endometrioid component showed retained SMARCA4 expression. An expanded survey of another member of the SWI/SNF complex showed SMARCB1 loss in the undifferentiated component of 2 SMARCA4-intact tumors. Subsequent immunohistochemical analysis of SMARCA4 and SMARCB1 was done in an additional set of 22 centrally reviewed dedifferentiated endometrial carcinomas and 31 grade 3 endometrioid carcinomas. Combining the results from the index and the expansion set, 15 of 30 (50%) of the dedifferentiated endometrial carcinomas examined showed either SMARCA4 loss (37%) or SMARCB1 loss (13%). The loss of SMARCA4 or SMARCB1 was mutually exclusive and occurred only in the undifferentiated component. All 31 grade 3 endometrioid carcinomas showed intact SMARCA4/SMARCB1 expression. The majority (73%) of the SMARCA4-deficient and half of SMARCB1-deficient undifferentiated component developed in a mismatch repair protein (MMR)-deficient molecular context. The observed spatial association between SMARCA4/SMARCB1 loss and histologic dedifferentiation suggests that loss of these SWI/SNF complex proteins may contribute to the development of dedifferentiated endometrial carcinoma.

No abstract

Although glyceraldehyde-3-phosphate dehydrogenase's (GAPDH) predilection for AU-rich elements has long been known, the expected connection between GAPDH and control of mRNA stability has never been made. Recently, we described GAPDH binding the AU-rich terminal 144 nt of the colony-stimulating factor-1 (CSF-1) 3 ¶ untranslated region (UTR), which we showed to be an mRNA decay element in ovarian cancer cells. CSF-1 is strongly correlated with the poor prognosis of patients with ovarian cancer. We investigated the functional significance of GAPDH's association with CSF-1 mRNA and found that GAPDH small interfering RNA reduces both CSF-1 mRNA and protein levels by destabilizing CSF-1 mRNA. CSF-1 mRNA half-lives were decreased by 50% in the presence of GAPDH small interfering RNA. RNA footprinting analysis of the 144 nt CSF-1 sequence revealed that GAPDH associates with a large AU-rich -containing region. The effects of binding of GAPDH protein or ovarian extracts to mutations of the AU-rich regions within the footprint were consistent with this finding. In a tissue array containing 256 ovarian and fallopian tube cancer specimens, we found that GAPDH was regulated in these cancers, with almost 50% of specimens having no GAPDH staining. Furthermore, we found that low GAPDH staining was associated with a low CSF-1 score (P = 0.008). In summary, GAPDH, a multifunctional protein, now adds regulation of mRNA stability to its repertoire. We are the first to evaluate the clinical role of GAPDH protein in cancer. In ovarian cancers, we show that GAPDH expression is regulated, and we now recognize that one of the many functions of GAPDH is to promote mRNA stability of CSF-1, an important cytokine in tumor progression.

We investigated if an adaptive radiotherapy approach based on cone beam CT (CBCT) acquired during radical treatment was feasible and resulted in improved dosimetric outcomes for bladder cancer patients compared to conventional planning and treatment protocol. A secondary aim was to compare a conventional plan with a theoretical online process where positioning is based on soft tissue position on a daily basis and treatment plan choice is based on bladder size. A conventional treatment plan was derived from a planning CT scan in the radical radiotherapy of five patients with muscle invasive bladder cancer. In this offline adaptive protocol using CBCT, the patients had 10 CBCT: daily CBCT for the first five fractions and then CBCT scan on a weekly basis. The first five daily CBCT in each patient were used to create a single adaptive plan for treatment from fraction eight onwards. A different process using the planning CT and the first five daily CBCT was used to create small, average and large bladder volumes, giving rise to small, average and large adaptive bladder treatment plans, respectively. In a retrospective analysis using the CBCT scans, we compared the clinical target volume (CTV) coverage using three protocols: (i) conventional; (ii) offline adaptive; and (iii) online adaptive with choice of 'plan of the day'. Daily CBCT prolonged treatment time by an average of 7 min. Two of the five patients demonstrated such variation in CTV that an offline adaptive plan was used for treatment after the first five CBCT. Comparing the offline adaptive plan with the conventional plan, the CTV coverage improved from a minimum of 60.1 to 94.7% in subsequent weekly CBCT. Using the CBCT data, modelling an online adaptive protocol showed that coverage of the CTV by the 95% prescribed dose line by small, medium and large adaptive plans were 34.9, 67.4 and 90.7% of occasions, respectively. More normal tissue was irradiated using a conventional CTV to planning target volume margin (1.5 cm) compared to an online adaptive process (0.5 cm). An offline adaptive strategy improves dose coverage in certain patients to the CTV and results in a higher conformity index compared to conventional planning. Further research in online adaptive radiation therapy for bladder cancer is indicated.

No abstract