Abstract PD01-02: Increased expression of phosporylated mTOR in metastatic breast tumors compared to primary tumors in patients who received adjuvant endocrine therapy

BACKGROUND: Activation of the PI3K pathway as an adaptive change in response to estrogen depletion results in acquired endocrine therapy resistance in vitro. Metastatic breast cancer patients with previous exposure to endocrine therapy do derive substantial benefit from the addition of an mTOR inhibitor to endocrine therapy compared to endocrine therapy alone. This suggests that compensatory PI3K pathway activation might play a role in the development of clinical resistance to endocrine therapy. We evaluated the activation of the downstream PI3K pathway protein mTOR in primary breast tumors and matched metastatic lesions.

METHODS: From a previously described series of breast cancer patients from whom both primary tumor tissue as well as metastatic tumor tissue was collected, we selected estrogen receptor α (ERα) positive patients who had received endocrine therapy (N = 34) and who did not receive endocrine therapy (N = 37). The difference in expression of phosphorylated mTOR (p-mTOR) between primary and metastatic tumor was assessed by immunohistochemistry, which was scored by using the proportion of tumor cells with sub-membranous p-mTOR expression. We assessed whether this p-mTOR difference between primary and metastatic tumor was associated with clinico-pathological factors (location of metastasis, lymph node status, T-stage, grade, progesterone receptor status) or varied between patients who did and did not receive endocrine therapy, using Mann-Whitney tests. In addition we performed a linear regression model including the same clinico-pathological factors.

RESULTS: In patients who had received endocrine therapy we observed an increase in p-mTOR expression in metastatic tumor lesions compared to the primary tumor (median difference 45%). This was significantly different from the mTOR changes observed in patients who did not receive endocrine therapy (median difference between metastatic and primary lesion 0 %) (p = 0.003). The difference remained significant in the multivariate regression model (p = 0.001). None of the other factors was significantly associated with a differential p-mTOR change.

CONCLUSION: In patients who received previous adjuvant endocrine therapy, the increase in p-mTOR expression in metastatic tumor lesions compared to the primary tumor is significantly higher than in patients who did not receive endocrine therapy. Compensatory activation of the PI3K pathway might therefore be a clinically relevant resistance mechanism resulting in secondary endocrine therapy resistance.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD01-02.

Abstract PD01-03: Phosphorylated p-70S6K predicts tamoxifen resistance in postmenopausal breast cancer patients randomized between adjuvant tamoxifen versus no systemic treatment

BACKGROUND: Activation of the PI3K/MAPK pathways results in anti-estrogen resistance in vitro, however a biomarker that can predict clinical resistance has not yet been identified. Common drivers of these pathways are PIK3CA mutations, loss of PTEN and over-expression of HER2 and IGF-1R. We aimed to test the prognostic and predictive value of PI3K/MAPK pathway drivers as well as downstream activated proteins in postmenopausal breast cancer patients.

METHODS: We collected primary tumor tissue from 563 ERα positive breast cancer patients who were randomized between tamoxifen (1–3 years) versus no adjuvant systemic therapy. PIK3CA hotspot mutations were assessed by Sequenom Mass Spectrometry. Immunohistochemistry was performed for expression of PTEN, IGF-1R and the downstream markers p-AKT(Thr308), p-AKT(Ser473), p-mTOR, p-p706SK and p-ERK1/2. Cox proportional hazard models for recurrence free interval were used to assess hazard ratios and interaction between these markers and treatment.

RESULTS: No significant interaction between any of the tested PI3K/MAPK pathways drivers and tamoxifen was found. [/bold]However, interactions were identified between tamoxifen and the downstream activated proteins (p-AKT(Thr308), p- mTOR, p-p70S6K and p-ERK1/2). After correcting for multiple testing, p-p70S6K remained significantly associated with tamoxifen resistance. Patients whose tumor did not express p-p70S6K did derive significant benefit from tamoxifen (HR 0.24, 95 % CI= 0.12–0.47, p < 0.0001), while patients whose tumor did express p-p70S6K did not (multivariate HR=1.02, 95% CI=0.48–2.21, p = 0.95), p for interaction 0.003.

CONCLUSION: We conclude that the downstream marker of PI3K/MAPK activation p-p70S6K predicts tamoxifen resistance in ERα positive postmenopausal breast cancer patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD01-03.

Mother's little helpers: Patterns of male care in mammals

Over the past 20 years, long-term studies have shown that mammalian fathers, brothers and even unrelated males may contribute substantially to the care of the young. Recently, more field studies of mammals with male care have further expanded interest in male care potential. Male mammals can never be sole care-givers because offspring depend on maternal milk, but assistance provided by males may allow females to produce more energetically costly litters. The need for such male care contributes to the development of obligate social monogamy or communal breeding.

Shin H, H. Lee K, Kim BJ. Reduced serum uric acid levels in neuromyelitis optica: serum uric acid levels are reduced during relapses in NMO

OBJECTIVES

Uric acid (UA), a product of purine metabolism, is known to be reduced in patients with various neurological disorders including multiple sclerosis (MS). However, it has still remained unclear whether there is a close relationship between UA and neuromyelitis optica (NMO). The aim of this study was to investigate the association between serum UA levels and disease activity in NMO.

METHODS

Retrospective analysis was made of blood samples during relapses (n = 48) and during stable disease (n = 49) from 20 patients with NMO. As controls, 59 blood samples during relapses from 39 patients with MS and 90 samples from healthy subjects were obtained. Spine magnetic resonance images (MRIs) performed during relapses (n = 24) in NMO were analysed.

RESULTS

The results indicated that UA levels during relapses in NMO were significantly lower compared to healthy subjects (P < 0.01), but not different from those during relapses in MS, and that reduced UA levels during relapses in NMO were normalized during stable disease. However, UA levels during relapses were not correlated with Gd enhancement in spine MRI.

CONCLUSION

UA levels are associated with clinical disease status in patients with NMO. Further investigations are recommended to elucidate the role of UA as a biomarker of disease activity in NMO.

J-pouch vs side-to-end coloanal anastomosis after preoperative radiotherapy and total mesorectal excision for rectal cancer: a multicentre randomized trial

AIM

Comparison of functional and surgical outcome of the J-pouch with the side-to-end coloanal anastomosis after preoperative radiotherapy and total mesorectal excision in rectal cancer patients.

METHOD

In a multicentre study, patients with a carcinoma of the lower two-thirds of the rectum were randomized to either a J-pouch or a side-to-end reconstruction. Primary outcome was function of the neorectum 1 year after surgery. A functional outcome [COloREctal Functional Outcome (COREFO)] questionnaire, and two quality of life questionnaires (EORTC-QLQ-CR38 and SF-36) were to be completed by all participants preoperatively, and 4 and 12 months postoperatively. Independent data managers recorded surgical outcome. A group size of 30 patients in each group was calculated based on a 15-point difference of the COREFO scale.

RESULTS

In total, 107 patients were randomized, 55 in the J-pouch group and 52 in the side-to-end anastomosis group. The COREFO incontinence scale at 4 months and the total functional outcome at 4 and 12 months showed better results for the J-pouch group in comparison with the side-to-end anastomosis group. The remaining COREFO scales (frequency, social impact, stool-related aspects and bowel medication), surgical outcome (complications, reoperations, length of hospital stay, readmissions and mortality) and quality of life did not show significant differences between treatment groups.

CONCLUSION

The overall results of a coloanal J-pouch and a side-to-end anastomosis are comparable, although functional results are slightly better with a J-pouch. The side-to-end anastomosis is technically less demanding and therefore a justified alternative in sphincter-saving surgery.

Myasthenia gravis and neuromyelitis optica spectrum disorder: a multicenter study of 16 patients

OBJECTIVE

To describe 16 patients with a coincidence of 2 rare diseases: aquaporin-4 antibody (AQP4-Ab)-mediated neuromyelitis optica spectrum disorder (AQP4-NMOSD) and acetylcholine receptor antibody (AChR-Ab)-mediated myasthenia gravis (AChR-MG).

METHODS

The clinical details and antibody results of 16 patients with AChR-MG and AQP4-NMOSD were analyzed retrospectively.

RESULTS

All had early-onset AChR-MG, the majority with mild generalized disease, and a high proportion achieved remission. Fifteen were female; 11 were Caucasian. In 14/16, the MG preceded NMOSD (median interval: 16 years) and 11 of these had had a thymectomy although 1 only after NMOSD onset. In 4/5 patients tested, AQP4-Abs were detectable between 4 and 16 years prior to disease onset, including 2 patients with detectable AQP4-Abs prior to thymectomy. AChR-Abs decreased and the AQP4-Ab levels increased over time in concordance with the relevant disease. AChR-Abs were detectable at NMOSD onset in the one sample available from 1 of the 2 patients with NMOSD before MG.

CONCLUSIONS

Although both conditions are rare, the association of MG and NMOSD occurs much more frequently than by chance and the MG appears to follow a benign course. AChR-Abs or AQP4-Abs may be present years before onset of the relevant disease and the antibody titers against AQP4 and AChR tend to change in opposite directions. Although most cases had MG prior to NMOSD onset, and had undergone thymectomy, NMOSD can occur first and in patients who have not had their thymus removed.