Postpartum breast cancer patients are at increased risk for metastasis compared to age-matched nulliparous or pregnant patients. Here, we address whether circulating tumor cells have a metastatic advantage in the postpartum host and find the post-lactation rodent liver preferentially supports metastasis. Upon weaning, we observed liver weight loss, hepatocyte apoptosis, ECM remodeling including deposition of collagen and tenascin-C, and myeloid cell influx, data consistent with weaning-induced liver involution and establishment of a pro-metastatic microenvironment. Using intracardiac and intraportal metastasis models, we observed increased liver metastasis in post-weaning Balb/c mice compared to nulliparous controls. Human relevance is suggested by a ~3-fold increase in liver metastasis in postpartum breast cancer patients (n=564) and by liver-specific tropism (n=117). In sum, our data reveal a previously unknown biology of the rodent liver, weaning-induced liver involution, which may provide insight into the increased liver metastasis and poor prognosis of women diagnosed with postpartum breast cancer.

The prognosis for small-bowel adenocarcinoma is worse than that for colon cancer, and only surgery improves survival. In contrast to colon cancer, a survival benefit from current chemotherapy regimens for small-bowel adenocarcinoma is not seen, suggesting that it may be overused and needs more rigorous study.

Although most patients with chronic myeloid leukemia (CML) treated with imatinib mesylate achieve a complete cytogenetic response (CCR), some patients will relapse. To determine the potential of real-time quantitative BCR-ABL reverse transcriptase-polymerase chain reaction (RT-PCR) to predict the duration of continued CCR, we monitored 85 patients treated with imatinib mesylate who achieved a CCR. With a median follow-up of 13 months after CCR (29 months after imatinib mesylate; median 6 RQ-PCR assays), 23 patients (27%) had disease progression (predominantly loss of CCR). Compared with the median baseline level of BCR-ABL mRNA, 42% of patients achieved at least a 2-log molecular response at the time of first reaching CCR. Failure to achieve a 2-log response at the time of CCR was an independent predictive marker of subsequent progressionfree survival (hazard ratio ‫؍‬ 5.8; 95% CI, 1.7-20; P ‫؍‬ .005). After CCR, BCR-ABL mRNA levels progressively declined for at least the next 15 months, and 42 patients (49%) ultimately achieved at least a 3-log reduction in BCR-ABL mRNA. Patients failing to achieve this 3-log response, at any time during therapy, had significantly shorter progression-free survival (hazard ratio ‫؍‬ 8.1; 95% CI, 3.1-22; P < .001). The achievement of either a 2-log molecular response at the time of CCR or a 3-log response anytime thereafter is a significant and independent prognostic marker of subsequent progressionfree survival. (Blood. 2006;107:4250-4256)