In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

[Q]: Context: Globally, heterosexual intercourse is the primary route of HIV-1 (HIV) transmission. It follows that mechanisms that protect against HIV infection are likely operative at the genital mucosa. In HIV-resistant Kenyan sex workers who are highly exposed to HIV infection yet remain uninfected, protection correlates with HIV-specific immune responses and genetic factors. However, these factors do not entirely explain this model of natural immunity to HIV. We hypothesized that protection may be mediated by innate immune proteins in the genital tract of HIV-resistant sex workers.', 'The genital proteome of mucosal secretions from HIV-resistant women was examined using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. Cervical lavage samples were collected from 315 HIV-resistant, HIV-uninfected and HIV-infected commercial sex workers.', 'Univariate analysis identified a 6 kDa biomarker of HIV resistance in genital secretions from these women. This protein was identified by tandem mass spectrometry as elafin and was found to be overexpressed in HIV-resistant women compared with HIV-uninfected (P = 0.001) and infected (P = 0.002) women. The elevated levels of elafin/trappin-2 in HIV-resistant women were confirmed using ELISA. The prospective association of elevated cervicovaginal elafin/trappin-2 levels with protection from HIV acquisition was then confirmed in an independent cohort of high-risk female sex workers.\Question: Does elevated elafin/trappin-2 in the female genital tract is associate with protection against HIV acquisition?
[A]: Using a unique proteomics approach in a large scale, cross-sectional cohort study, we identified elafin/trappin-2 as a novel innate immune factor, which is highly associated with resistance. This association was confirmed within an independent, prospective cohort study. Genital tract elafin/trappin-2 levels constitute a natural correlate of HIV protection in humans.

[Q]: Context: Accumulating evidence has indicated that inflammation may act as a potential mechanism underlying post-operative cognitive dysfunction (POCD). High-mobility group box 1 (HMGB1), as a known late mediator of inflammation, is involved in the development of post-operative complications. Thus, we sought to determine the role of HMGB1 in reflecting POCD following major gastrointestinal surgery.', 'Fifty-three elderly patients undergoing gastrointestinal surgery were recruited, and 50 patients completed the study. Serum HMGB1 and interleukin (IL)-6 levels were measured pre-operatively and at 6 h, day 1 and day 3 post-operatively. Neuropsychological tests were administered before and 1 week after surgery. POCD was determined using a Z score 1.96.', 'Seventeen (34%, 17/50) patients developed POCD at 1 week. The POCD group had higher serum HMGB1 levels at day 1 (12.15 3.12 vs. 9.91 3.15 ng/ml, P = 0.021) and day 3 (11.04 2.88 vs. 8.52 3.31 ng/ml, P = 0.011). IL-6 levels at 6 h (51.18 15.22 vs. 39.20 14.32 pg/ml, P = 0.009) and day 1 (41.59 11.08 vs. 33.81 11.42 pg/ml, P = 0.026) were significantly higher in POCD patients. Serum values of IL-6 at 6 h, HMGB1 at day 1 and levels of education showed positive correlations with Z scores. HMGB1 at day 3 and IL-6 at 6 h were independent risk factors.\Question: Does serum high-mobility group box 1 protein correlate with cognitive decline after gastrointestinal surgery?
[A]: Serum HMGB1 and IL-6 levels increase significantly after major gastrointestinal surgery in elderly patients and such elevations are associated with the occurrence of cognitive decline after surgery.

[Q]: Context: BACKGROUND/AIMs: Pleiotrophin (PTN) have been demonstrated to play an important role in the development of human gastric cancer. However, the prognostic value remains unclear. The aim of this study was to investigate whether expression of PTN has prognostic relevance in human gastric cancer.', 'Immunohistochemistry was used to investigate the expression of PTN proteins in 178 patients with gastric cancer. The level of PTN mRNA in gastric cancer tissues and paratumor tissues were evaluated in 52 paired cases by quantitative real-time polymerase chainreaction(qRT-PCR). Survival analysis by the Kaplan-Meier method was performed to assess prognostic significance.', 'The expression level of PTN in gastric cancer tissues was significantly higher (P<0.001) than those in paratumor tissues according to the immunohistochemistry analysis, which was confirmed by qRT-PCR analysis. Additionally, the overexpression of PTN was significantly associated with the tumor site (P=0.001), Lauren's classification (P<0.001),histologic differentiation(P=0.014),depth of invasion(P<0.001), TNM stage (P=0.003),and lymph node metastasis (P=0.002). Moreover, the Cox proportional- hazards regression analysis revealed that the increased expression of PTN was an independent prognostic factor for poor recurrence-free survival(RFS) and overall survival(OS)(both P<0.001).\Question: Is increased expression of pleiotrophin a prognostic marker for patients with gastric cancer?
[A]:
These findings indicated that the expression of PTN is significantly correlated with prognosis in gastric cancer patients, suggesting that the expression of PTN may be used as an independent prognostic marker.