Retinoid X receptor alpha (RXRα) and peroxisome proliferator-activated receptor gamma (PPARγ) expression in breast cancer: an immunohistochemical study

BACKGROUND/AIM

The role of retinoid X receptor alpha (RXRα) and peroxisome proliferator-activated receptor gamma (PPARγ) in breast cancer has been well studied in vitro. The aim of the study was to assess the presence of these molecules in human breast cancer specimens and correlate them with major clinicopathological features.

PATIENTS AND METHODS

Tissue sections from 82 breast cancer cases clustered according to histological grade, lymph node (LN) and hormone receptor (HR) status were assessed by immunohistochemistry for RXRα and PPARγ.

RESULTS

RXRα was found to be strongly and moderately expressed in 11 (14.10%) and 33 (42.31%) cases, respectively. PPARγ was found to be strongly and moderately expressed in 33 (41.25%) and 25 (31.25%) cases, respectively. Only RXRα expression was inversely correlated with histological grade. Surprisingly, significantly elevated PPARγ expression was found in cases with positive LN status. Survival analysis did not yield significant results.

CONCLUSION

Our data support the current thesis of RXRα being a potential target for feature molecular interventions.

[Neoadjuvant therapy of breast cancer]

Whereas in the past primary systemic therapy (PST) was rather used for other tumor entities or was limited to the use in inoperable breast cancer, treatment of operable stages is being increasingly investigated. After the proof of equivalency between PST and adjuvant chemotherapy, numerous trials have been conducted. PST enables testing of in vivo chemosensitivity; thus, treatment can be monitored by tumor response. Insufficient responders can be switched to non-cross-resistant concepts to avoid administration of ineffective drugs and try to achieve improvement of survival for these patients. The reduction of tumor size not only increases the rate of breast-conserving therapy, but has predictive value for the further course of the disease. Especially pathohistological complete remission is a good surrogate marker for improved survival and the goal of modern protocols in the preoperative setting. Actively recruiting trials (e.g. trials of the AGO PREPARE and TECHNO) integrate modern concepts of treatment like dose-dense, dose-intensified, sequential therapy and tumor targeting with trastuzumab in PST. Eligible patients should be recruited in ongoing trials to further elucidate the role of PST in primary breast cancer. Evaluation of predictive factors and correlation of therapy response to the genetic profile of the tumor with modern technologies will allow improved selection of patients with increasingly tailored therapy.

[Stabilization of lung function in cystic fibrosis during long-term tube feeding via a percutaneous endoscopic gastrostomy]

To determine whether long-term enteral feedings can improve nutritional status and lung function parameters in patients with cystic fibrosis (CF), 11 patients (8 female, 3 male, age 7 to 23 years) received a percutaneous endoscopic gastrostomy (PEG) since February 1988. All patients were moderately to severely affected and extremely malnourished with a relative underweight of 15% or more. After 9 months of supplemental nocturnal feeding, mean body weight improved from 25.8 +/- 4.7 kg (mean, standard deviation) to 31.6 +/- 7.4 kg (p = 0.003); mean relative underweight decreased from 20.7 +/- 3.4% to 10.4 +/- 8.6% (p = 0.02). Lung function, which was measured either prior to or without any intravenous antibiotics, improved considerably: mean vital capacity increased from 39.5% of the predicted value to 46.8% after 9 months (p = 0.01), the mean peak flow rate improved from 39.5% to 50.8% (p = 0.01). This improvement in lung function is probably secondary to the increased muscle mass of the patients. Long-term nocturnal feedings via a percutaneous gastrostomy tube improve nutritional status and lung function severely in malnourished patients with CF.