Localization of tamoxifen in human breast cancer tumors by MALDI mass spectrometry imaging

Clinical and Translational Medicine

Table 1 Summary of image analysis

Sample	Area	Mean signal intensity	Ratio of mean intensities
21296/ER−
Tumor	20,633	141.956	0.961
Stroma	51,585	147.683
21498/ER−
Tumor	46,556	14.861	0.555
Stroma	174,838	26.79
21505/ER−
Tumor	57,135	35.279	1.082
Stroma	121,614	32.601
21524/ER−
Tumor	41,870	71.572	0.779
Stroma	99,257	91.917
21506/ER+
Tumor	4198	60.243	1.138
Stroma	176,973	52.923
21508/ER+
Tumor	29,101	62.652	0.849
Stroma	87,341	73.769
21509/ER+
Tumor	45,132	14.877	1.278
Stroma	120,119	11.637
21557/ER+
Tumor	28,673	28.369	1.151
Stroma	62,461	24.643

The mean signal intensity of the tamoxifen precursor ion (m/z 372.233) was determined in annotated tumor and stroma regions within each tissue section using the normalized MS images. The ratios of mean intensities (tumor/stroma) were calculated for statistical t test that showed significant differences between the ER groups (p = 0.01)