Ryuichi Yoshida

Chromogranin A and chromogranin B in noninvasive and invasive breast carcinoma

Recent progress in the study of chromogranins has revealed that there are many novel peptides derived from chromogranin with their multiple pathophysiologic roles. To learn the possible roles of chromogranin in breast carcinoma, we immunohistochemically investigated tissue localization of chromogranin A (CgA) and chromogranin B (CgB) in 10 normal breast tissues, 23 noninvasive ductal carcinomas (NIDCs), and 169 invasive ductal carcinomas (IDCs) and compared their expression with estrogen receptor (ER), progesterone receptor (PR), and Ki67. CgA and CgB were sporadically detected in normal cells of the ducts, acini, and luminal secretion. The expression of CgA and CgB was higher in NIDCs than in IDCs: CgA=70% of NIDC vs 22% of IDC and CgB=65% of NIDC vs 30% of IDC. There was a statistical correlation between the expression of CgA and PR (p < 0.05) and CgB and ER (p < 0.05) in IDCs without lymph node metastasis. On the other hand, there was a significant correlation between expression of CgB and PR and an inverse correlation between CgA and Ki67 in IDCs of overall cases. The data suggest that CgA and CgB may play some role in the early phase of neoplastic progression.

Quantitative diagnostic imaging of cancer tissues by using phosphor-integrated dots with ultra-high brightness

The quantitative sensitivity and dynamic range of conventional immunohistochemistry (IHC) with 3,3′-diaminobenzidine (IHC-DAB) used in pathological diagnosis in hospitals are poor, because enzyme activity can affect the IHC-DAB chromogenic reaction. Although fluorescent IHC can effectively increase the quantitative sensitivity of conventional IHC, tissue autofluorescence interferes with the sensitivity. Here, we created new fluorescent nanoparticles called phosphor-integrated dots (PIDs). PIDs have 100-fold greater brightness and a more than 300-fold greater dynamic range than those of commercially available fluorescent nanoparticles, quantum dots, whose fluorescence intensity is comparable to tissue autofluorescence. Additionally, a newly developed image-processing method enabled the calculation of the PID particle number in the obtained image. To quantify the sensitivity of IHC using PIDs (IHC-PIDs), the IHC-PIDs method was compared with fluorescence-activated cell sorting (FACS), a method well suited for evaluating total protein amount, and the two values exhibited strong correlation (R = 0.94). We next applied IHC-PIDs to categorize the response to molecular target-based drug therapy in breast cancer patients. The results suggested that the PID particle number estimated by IHC-PIDs of breast cancer tissues obtained from biopsy before chemotherapy can provide a score for predicting the therapeutic effect of the human epidermal growth factor receptor 2-targeted drug trastuzumab.

OLFM4, LY6D and S100A7 as potent markers for distant metastasis in estrogen receptor-positive breast carcinoma

Metastatic breast cancer is a highly lethal disease, and it is very important to evaluate the biomarkers associated with distant metastasis. However, molecular features of distant metastasis remain largely unknown in breast cancer. Estrogens play an important role in the progression of breast cancer and the majority of stage IV breast carcinomas express estrogen receptor (ER). Therefore, in this study, we examined molecular markers associated with distant metastasis in ER‐positive breast carcinoma by microarray and immunohistochemistry. When we examined the gene expression profile of ER‐positive stage IV breast carcinoma tissues (n = 7) comparing ER‐positive stage I‐III cases (n = 11) by microarray analysis, we newly identified OLFM4, LY6D and S100A7, which were closely associated with the distant metastasis. Subsequently, we performed immunohistochemistry for OLFM4, LY6D and S100A7 in 168 ER‐positive breast carcinomas. OLFM4, LY6D and S100A7 immunoreactivities were significantly associated with stage, pathological T factor, distant metastasis and Ki67 status in the ER‐positive breast carcinomas. Moreover, these immunoreactivities were significantly associated with a worse prognostic factor for distant metastasis‐free and breast cancer‐specific survival in ER‐positive stage I‐III breast cancer patients. However, when we performed immunohistochemistry for OLFM4, LY6D and S100A7 in 40 ER‐negative breast carcinomas, these immunoreactivities were not generally associated with the clinicopathological factors examined, including distant metastasis and prognosis of patients, in this study. These results suggest that OLFM4, LY6D and S100A7 immunoreactivity are associated with an aggressive phenotype of ER‐positive breast carcinoma, and these are potent markers for distant metastasis of ER‐positive breast cancer patients.