Study of Gene Expression of Programmed Cell Death Ligand 1 (PD-L1) in Breast Cancer Patients

Introduction:

Breast cancer is the most frequently occurring cancer among females and the second most common cancer overall. Programmed Cell Death Ligand 1 (PD-L1) plays an important role in blocking ‘cancer-immunity cycle’ and is considered as a major inhibitory pathway. The aim of the present study was to clarify the alterations of expression of PD-L1 in peripheral blood mononuclear cytes (PBMCs) of female breast cancer patients and analyze its association with clinico-pathological criteria as well as therapeutic response.

Materials and Methods:

The study was conducted on 45 female breast cancer patients and 45 female controls. Blood samples were collected followed by PBMCs isolation, total RNA extraction, reverse transcription and finally, quantitative polymerase chain reaction (qPCR) using SYBR Green DNA binding dye. Expression levels of PD-L1 were calculated and then compared with clinicopathological parameters of the patients in addition to initial therapeutic response.

Results:

A significant difference was detected for PD-L1 expression levels in breast cancer patients compared to controls. A significant association with age, metastatic breast cancer, estrogen receptor (ER) negative status as well as high concentrations of cancer antigen 15-3 (CA15-3) was detected. On the other hand, no significant association was recognized with tumor size, lymph nodal status, histopathological type, grade, progesterone receptor (PR) status, human epidermal growth factor receptor 2 (HER-2) status, triple negative, among de novo and recurrent metastatic patients and for the number of metastatic sites as well as the therapeutic response.

Conclusions:

This study paves the way of the use of PD-L1 as a noninvasive prognostic and diagnostic biomarker for poor prognosis of breast cancer.

Effect of standard and high dose ranitidine on [13C]urea breath test results

OBJECTIVE

It has been suggested that standard dose H2 blockers will affect the [14-C]urea breath test. The aim of this study was to evaluate the effect of standard and high dose ranitidine on the [13C]urea breath test in a prospective cross-over study.

METHODS

Volunteers found to be positive for H. pylori by IgG serology and [13C]urea breath test were given either ranitidine 150 mg b.i.d. or 300 mg b.i.d. for 14 days. Repeat breath tests were completed on the last day of antisecretory dosing and study patients were immediately crossed over to the other ranitidine dose. The third breath test was performed at 14 days after initiation of the new dose.

RESULTS

A total of 20 volunteers were enrolled. Using the established cut-off of 2.4% for the commercial breath test, only one patient developed negative results on H2 blockers. This patient had negative breath tests on both ranitidine doses and remained test-negative off all medications 6 wk after study completion, suggesting either a false positive baseline test or an unexpected bacterial eradication. No specific trend in breath test results was observed for the group (p=NS). On ranitidine 300 mg, six of 19 patients elevated their breath results from 23% to 112% (mean 76%) above baseline.

CONCLUSION

Ranitidine at standard or high doses did not generate a reproducible decline in breath test results. Histamine 2 blockers do not need to be discontinued before urea breath testing.