instruction:
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.
question:
Context: To investigate a putative increased risk of rectal cancer subsequent to prostatic radiotherapy.', 'In an analysis of the Surveillance, Epidemiology, and End Results registry, we compared men who had radiotherapy for prostatic carcinoma with those treated surgically and those treated with neither modality. Kaplan-Meier analyses for the time to failure from rectal cancer were performed between age-matched subgroups of the three cohorts. Cox proportional hazards analyses were performed to ascertain what influences might affect the incidence of subsequent rectal cancer.', 'In all, 33,831 men were irradiated, 167,607 were treated surgically, and 36,335 received neither modality. Rectal cancers developed in 243 (0.7%) of those irradiated (mean age, 70.7 years), 578 (0.3%) of those treated surgically (68.7 years), and 227 (0.8%) of those treated with neither modality (74.2 years). When age effects and the differences between the surgical and untreated cohorts were controlled for, we were unable to demonstrate any significant increased incidence of rectal cancer in men irradiated for prostatic cancer.
Answer: An increased frequency of rectal cancer after prostatic irradiation, apparent on crude analysis, could be attributed to age confounding and other unmeasured confounders associated with prostate cancer treatment and rectal cancer risk.
answer:
Is prostatic irradiation associated with any measurable increase in the risk of subsequent rectal cancer?


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Context: The ability to achieve significant donor engraftment without fully myeloablative conditioning has revolutionized allogeneic stem cell transplantation. These nonmyeloablative approaches may allow extension of this potentially curative modality to an increasing number of patients including those with non-malignant diseases. Although a number of regimens have been explored, the optimal means of conditioning has not been determined.', 'We previously demonstrated that rapamycin (RAPA) has the ability to promote T-cell tolerance even in the presence of costimulation. In the current study, we examine the ability of rapamycin or the calcineurin inhibitor cyclosporine A (CSA) to promote chimerism in a murine haploidentical bone marrow transplantation model. Mice were conditioned with 300 cGy and received either RAPA at 3 mg/kg/day IP, CSA at 20 mg/kg/day IP, or no immunosuppression starting on the day before the transplant and continued for 4 weeks.', 'There was no apparent toxicity, and animals maintained normal blood counts throughout. More importantly, long-term macrochimerism was observed only in the RAPA-treated group.
Answer: These results establish a simple, nontoxic, irradiation-based regimen that facilitates engraftment without ablation. This strategy may prove useful in nonmalignant disorders such as hemoglobinopathies in which moderate levels of donor chimerism could prove curative.
answer:
Does low-dose radiation plus rapamycin promote long-term bone marrow chimerism?


question:
Context: C-type natriuretic peptide (CNP) is an important regulator of skeletal growth. Loss-of-function mutations affecting the CNP receptor natriuretic peptide receptor-B (gene NPR2) cause the autosomal recessive skeletal dysplasia, acromesomelic dysplasia, Maroteaux type (AMDM). The phenotype of heterozygous carriers of NPR2 mutations is less clear.', 'The objective of the study was to determine the phenotypic features of heterozygous carriers of NPR2 mutations.', 'This was a case-control study from the general community.', 'Thirty-nine members of a family in which one member has AMDM were studied.', 'This was an observational study.', 'The primary measure was stature, with the hypothesis that carriers have reduced stature compared with noncarriers.', 'Sixteen family members were NPR2 mutation carriers. Height z-scores of these carriers were -1.8 +/- 1.1 (mean +/- sd), which was significantly less than the 23 noncarrier family members (-0.4 +/- 0.8, P < 0.0005) and the general population (P < 0.0005). However, there was no difference in body proportion between carriers and noncarriers. The proband with AMDM had low IGF-I levels and evidence of GH resistance, as well as very high plasma levels of CNP and its amino-terminal propeptide. Levels of these peptides were normal in the heterozygous carriers.
Answer: We have shown that heterozygous mutations in NPR2 are associated with short stature. Assuming one in 700 people unknowingly carry an NPR2 mutation, our data suggest that approximately one in 30 individuals with idiopathic short stature are carriers of NPR2 mutations.
answer:

Are heterozygous mutations in natriuretic peptide receptor-B ( NPR2 ) associated with short stature?