Transcriptional CCND1 expression as a predictor of poor response to neoadjuvant chemotherapy with trastuzumab in HER2-positive/ER-positive breast cancer.

Several trials have confirmed that the pathological complete response (pCR) rates after neoadjuvant chemotherapy (NAC) are significantly lower in HER2-positive/ER-positive patients than in HER2-positive/ER-negative patients. To understand this phenomenon, we investigated the association between NAC resistance and CCND1, which is frequently overexpressed in ER-positive tumors. Pretreatment formalin-fixed tumor tissues were collected from 75 HER2-positive patients receiving NAC comprised anthracyclines, taxanes, and trastuzumab. Seventeen gene transcripts along with PIK3CA mutations were detected using MassARRAY (Sequenom, San Diego, CA). The gene expression levels were dichotomized according to the median values. The immunohistochemical expression of ER, PTEN, BCL-2, and cyclin D1 was scored. The relationship between the variables was assessed using the Spearman correlation. A logistic regression analysis was performed to detect predictors of pCR, which was defined as no invasive tumor in the breast or axilla. Forty-seven percent of the cases were ER-positive and 52 % (40/63 % in ER-positive/ER-negative) achieved a pCR. Among the ER-positive patients, the CCND1 gene expression level was 2.1 times higher than that in ER-negative patients and was significantly correlated with the expression of cyclin D1 protein. In a univariate analysis, a pCR was associated with high mRNA levels of ESR1, PGR, LMTK3, HER2, IGF1R, INPP4B, PDL-1, BCL-2, and CCND1 (P ≤ 0.05). In contrast, none of these genes were significantly correlated with a pCR among the ER-negative tumors and only EGFR was significantly correlated with a pCR. PIK3CA mutations or PTEN loss were not associated with a pCR in either group. After excluding ESR1 (r = 0.58), PGR (r = 0.64), and IGF1R (r = 0.59), the expressions of which were correlated with CCND1, a multivariate analysis revealed that CCND1 [P = 0.043; OR, 0.16] and HER2 [P = 0.012; OR, 11.2] retained its predictive value for pCR among ER-positive patients, but not among ER-negative patients. A High Level of CCND1 gene expression is a poor predictor of a pCR and provides a rationale for evaluating CDK4/6 inhibitors in HER2-positive/ER-positive breast cancer patients.

Long-term changes in open field activity of male mice irradiated with low levels of gamma rays at late stage of development.

The open field activity of first generation (F1) hybrid male C57BL/6 x C3H mice irradiated with gamma-rays on the 14th day of gestation was studied at the following ages: 6-7 months, 12-13 months and 19-20 months. Doses were 0.1 Gy or 0.2 Gy. Open field activity was recorded with a camera. The camera output signal was recorded every sec through an A/D converter to a personal computer. The field was divided into 25 units of 8 cm square. All recordings were continuous for 60 min. The time which the 0.2-Gy group recorded at 6-7 months, spent in the 4 squares in the corner fields was high in comparison with the control group at the same age. The walking distance of the 0.1-Gy group recorded at 12-13 months was longer than that for the age matched control group. No effect of radiation was found on any of the behaviors observed and recorded at 19-20 months. The results demonstrate that exposure to low levels of gamma-rays on the 14th day of gestation results in behavioral changes, which occur at 6-7 and 12-13 months but not 19-20 months.

Long-term effects of prenatal exposure to low levels of gamma rays on open-field activity in male mice.

The open-field activity of first-generation (F1) hybrid male C57BL/6 x C3H mice irradiated with gamma rays on day 14 of gestation was studied at the following ages: 6-7 months (young), 12-13 months (adult) and 19-20 months (old). Doses were 0.5 Gy or 1.0 Gy. Open-field activity was recorded with a camera. The camera output signal was recorded every second through an A/D converter to a personal computer. The field was divided into 25 8-cm2 units. All recordings were continuous for 60 min. The walking speed of the 1.0-Gy group recorded at 19-20 months was higher than that for the comparably aged control group. The time which the irradiated group, recorded at 19-20 months, spent in the corner fields was high in comparison with the control group at the same age. Conversely, the time spent by the irradiated group in the middle fields when recorded at 19-20 months was shorter than in the comparably aged control group. No effect of radiation was shown for any of the behaviors observed and recorded at 6-7 and 12-13 months. The results demonstrate that such exposure to gamma rays on day 14 of gestation results in behavioral changes which occur at 19-20 months but not at 6-7 or 12-13 months.

Long term effects of prenatal exposure to low level gamma rays on spontaneous circadian motor activity of male mice.

The spontaneous circadian motor activity of first generation (F1) hybrid male C57BL/6xC3H mice irradiated with gamma rays on the 14th day of gestation was studied at the following ages: young (6-7 months), adult (12-13 months), and old (19-20 months). Doses were 0.1, 0.2, 0.5 or 1.0 Gy. A 12-hour day-night cycle was maintained with light on a at 6:00 hr. Spontaneous circadian motor activity was recorded with a capacitance-induction motility monitor for 48 consecutive hours. Activity was measured at 2-hour intervals, and the data stored on computer discs. The activity of the 1.0 Gy group recorded at 22:00 and 2:00 hr for young mice and at 2:00 hr for adult ones was significantly higher than that of the age-matched control group. Results suggest that male mice irradiated with 1.0 Gy at gestational day 14 show nocturnal hyperactivity in the young and adult stages.

Effects of fetal exposure to gamma rays on aggressive behavior in adult male mice.

Aggressive behavior (AB) in first generation (F1) hybrid male C57BL/6xC3H mice irradiated on the 14th day of gestation was studied at 100-135 days of age. Gravid female mice were irradiated with 1.0 or 2.0 Gy of gamma rays to the whole body. The AB of pairs of mice were recorded with a capacitance-induction motility monitor and on videotape. Recordings were continued for 90 min, starting at 2:00 PM. Vigorous wrestling, boxing and biting were regarded as AB. Data recorded at 15-min intervals were stored on micro-computer discs. The body weight for the irradiated group was significantly lower than that for the control group. The number of instances of AB was significantly higher in the irradiated group. The AB of the 2.0 Gy group was significantly more intensive than that of the control group. No difference in the duration of AB was found for the 2 irradiated and the control groups. Results demonstrate that male mice irradiated prenatally show increased aggressiveness.

Gross morphological changes of the mouse brain exposed prenatally to ionizing radiation.

Gross morphological changes of the brains of first generation (F1) C57BL/6 x C3H hybrid male mice irradiated prenatally were studied at 6 months of age. Gravid female mice were irradiated with 1.0 Gy, 2.0 Gy or 3.0 Gy of gamma radiation on the 14th day of gestation. The brain in dorsal view was photographed. The measurements of the area and the distance of parts of the brain were made from photographs, using a computer system for biological image analysis. The body and brain weight and the area and length of the cerebral hemispheres (CHs) showed dose-related decrease. There was a dose related increase in the area of the superior colliculi (SC), the distance (DP) from the point which the medial walls of the CHs begin to slope away from the midline to the posterior end of CHs, and the proportion of the DP to the CH length. From the results of the dose-response curve, it appears that the area of the SC and the proportion of DP to CH length are affected by small doses of less than 1.0 Gy.