Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

[EX Q]: Context: The aim of this study was to determine the effects of exogenous expression of the catalytic subunit of telomerase (hTERT) on the lifespan, growth characteristics, and tumorigenicity of normal human ovarian surface epithelial (OSE) cells.', 'Low-passage primary cultures of normal human OSE cells were transfected with hTERT and the resulting cell lines were characterized.', 'The ectopic expression of hTERT stabilized the telomeres of the OSE cultures above 8 kb. The hTERT-transfected OSE cell lines grew beyond the normal lifespan seen in OSE cells and propagated in culture for more than 40 passages before senescing. Moreover, the hTERT-transfected cells demonstrated extensive proliferative capacity as evidenced by their ability to continuously grow even when seeded at low dilutions. The morphologic features and normal differentiation patterns seen in normal OSE cells were likewise retained by the hTERT-transfected cells. In addition, the cultures remained responsive to physiologic concentrations of epidermal growth factor and transforming growth factor-beta. Changes associated with neoplastic transformation like anchorage-independent growth, tumorigencity and karyotypic instability were not observed.
Answer: We were able to show that the ectopic expression of hTERT in normal human OSE: 1) resulted in cultures with greater growth potential and longer lifespan and 2) did not induce a transformed phenotype previously seen in viral oncogene-transfected OSE cells. The established cell lines would not only provide sufficient material for comprehensive studies to investigate the normal physiology of OSE cells, but could also help in the understanding of the early steps of ovarian carcinogenesis.
[EX A]: Does telomerase prolong the lifespan of normal human ovarian surface epithelial cells without inducing neoplastic phenotype?

[EX Q]: Context: Current staging for renal cancer (RC) does not directly rely on tumor size. We examined the increment in accuracy related to inclusion of pathologically determined tumor size in prediction of nodal metastases (N+), distant metastases (M+), and cancer-specific survival (CSS).', 'Partial or radical nephrectomy was performed in 2245 patients with clear cell histology. Pathologic stages were T1a in 566, T1b in 490, T2 in 303, T3 in 831, and T4 in 55 patients. Tumor size was 0.5-25 cm (mean, 6.8). Multivariate models relied on 1997 and 2002 TNM variables and addressed N+, M+ disease, and CCS. Their accuracy was compared according to either the presence or absence of tumor size.', 'In all univariate and multivariate models, tumor size was a statistically significant predictor of all outcomes (p< or =0.001). In all multivariate models, tumor size added between 3.7% and 0.8% to predictive accuracy of either 1997 or 2002 TNM categories.
Answer: Tumor size represents a highly significant, multivariate, and informative predictor of RC outcomes and may warrant inclusion in future TNM revisions.
[EX A]: Does tumor size improve the accuracy of TNM predictions in patients with renal cancer?

[EX Q]: Context: The aim of this study was to analyze prosthetic maintenance in partially edentulous patients with removable prostheses supported by teeth and strategic implants.', 'Sixty patients with removable partial prostheses and combined tooth-implant support were identified within the time period from 1998 to 2006. One group consisted of 42 patients (planned group) with a reduced residual dentition and in need of removable partial dentures (RPDs) or overdentures in the maxilla and/or mandible. They were admitted consecutively for treatment. Due to missing teeth in strategic important positions, one or two implants were placed to improve symmetrical denture support and retention. The majority of residual teeth exhibited an impaired structural integrity and therefore were provided with root copings for denture retention. A few vital teeth were used for telescopic crowns. The anchorage system for the strategic implants was selected accordingly. A second group of 18 patients (repair group) wearing RPDs with the loss of one abutment tooth due to biologic or mechanical failure was identified. These abutment teeth were replaced by 21 implants, and patients continued to wear their original prostheses. The observation time for planned and repair groups was 12 months to 8 years. All patients followed a regular maintenance schedule. Technical or biologic complications with supporting teeth or implants and prosthetic service were registered regularly.', 'Three maxillary implants were lost after loading and three roots with copings had to be removed. Biologic problems included caries and periodontal/peri-implant infection with a significantly higher incidence in the repair group (P < .05). Technical complications with the dentures were rather frequent in both groups, mostly related to the anchorage system (matrices) of root copings and implants. Maintenance and complications were observed more frequently in the first year after delivery of the denture than in the following 3 years (P < .05). No denture had to be remade.
Answer: The placement of a few implants allows for maintaining a compromised residual dentition for support of RPDs. The combination of root and implant support facilitates treatment planning and enhances designing the removable denture. It also proves to be a practical rescue method. Technical problems with the anchorage system were frequent, particularly in the first year after delivery of the dentures.
[EX A]:
Do removable dentures with implant support in strategic positions followed for up to 8 years?