Postpartum breast cancer: mechanisms underlying its worse prognosis, treatment implications, and fertility preservation.

Breast cancers that occur in young women up to 5 to 10 years' postpartum are associated with an increased risk for metastasis and death compared with breast cancers diagnosed in young, premenopausal women during or outside pregnancy. Given the trend to delay childbearing, this frequency is expected to increase. The (immuno)biology of postpartum breast cancer is poorly understood and, hence, it is unknown why postpartum breast cancer has an enhanced risk for metastasis or how it should be effectively targeted for improved survival. The poorer prognosis of women diagnosed within 10 years of a completed pregnancy is most often contributed to the effects of mammary gland involution. We will discuss the most recent data and mechanistic insights of the most important processes associated with involution and their role in the adverse effects of a postpartum diagnosis. We will also look into the effect of lactation on breast cancer outcome after diagnosis. In addition, we will discuss the available treatment strategies that are currently being used to treat postpartum breast cancer, keeping in mind the importance of fertility preservation in this group of young women. These additional insights might offer potential therapeutic options for the improved treatment of women with this specific condition.

Breast Cancer Detection and Treatment Monitoring Using a Noninvasive Prenatal Testing Platform: Utility in Pregnant and Nonpregnant Populations.

BACKGROUND: Numerous publications have reported the incidental detection of occult malignancies upon routine noninvasive prenatal testing (NIPT). However, these studies were not designed to evaluate the NIPT performance for cancer detection. METHODS: We investigated the sensitivity of a genome-wide NIPT pipeline, called GIPSeq, for detecting cancer-specific copy number alterations (CNAs) in plasma tumor DNA (ctDNA) of patients with breast cancer. To assess whether a pregnancy itself, with fetal cell-free DNA (cfDNA) in the maternal circulation, might influence the detection of ctDNA, results were compared in pregnant (n = 25) and nonpregnant (n = 25) cancer patients. Furthermore, the ability of GIPSeq to monitor treatment response was assessed. RESULTS: Overall GIPSeq sensitivity for detecting cancer-specific CNAs in plasma cfDNA was 26%. Fifteen percent of detected cases were asymptomatic at the time of blood sampling. GIPSeq sensitivity mainly depended on the tumor stage. Also, triple negative breast cancers (TNBC) were more frequently identified compared to hormone-positive or HER2-enriched tumors. This might be due to the presence of high-level gains and losses of cfDNA or high ctDNA loads in plasma of TNBC. Although higher GIPSeq sensitivity was noted in pregnant (36%) than in nonpregnant women (16%), the limited sample size prohibits a definite conclusion. Finally, GIPSeq profiling of cfDNA during therapy allowed monitoring of early treatment response. CONCLUSIONS: The results underscore the potential of NIPT-based tests, analyzing CNAs in plasma cfDNA in a genome-wide and unbiased fashion for breast cancer detection, cancer subtyping and treatment monitoring in a pregnant and nonpregnant target population.

Fecal virome analysis of three carnivores reveals a novel nodavirus and multiple gemycircularviruses.

BACKGROUND: More knowledge about viral populations in wild animals is needed in order to better understand and assess the risk of zoonotic diseases. In this study we performed viral metagenomic analysis of fecal samples from three healthy carnivores: a badger (Meles meles), a mongoose (Herpestes ichneumon) and an otter (Lutra lutra) from Portugal. RESULTS: We detected the presence of novel highly divergent viruses in the fecal material of the carnivores analyzed, such as five gemycircularviruses. Four of these gemycircularviruses were found in the mongoose and one in the badger. In addition we also identified an RNA-dependent RNA polymerase gene from a putative novel member of the Nodaviridae family in the fecal material of the otter. CONCLUSIONS: Together these results underline that many novel viruses are yet to be discovered and that fecal associated viruses are not always related to disease. Our study expands the knowledge of viral species present in the gut, although the interpretation of the true host species of such novel viruses needs to be reviewed with great caution.

Poor Outcome in Postpartum Breast Cancer Patients Is Associated with Distinct Molecular and Immunologic Features.

PURPOSE: Patients with postpartum breast cancer diagnosed after cessation of breastfeeding (postweaning, PP-BCPW) have a particularly poor prognosis compared with patients diagnosed during lactation (PP-BCDL), or to pregnant (Pr-BC) and nulliparous (NP-BC) patients, regardless of standard prognostic characteristics. Animal studies point to a role of the involution process in stimulation of tumor growth in the mammary gland. However, in women, the molecular mechanisms that underlie this poor prognosis of patients with PP-BCPW remain vastly underexplored, due to of lack of adequate patient numbers and outcome data. EXPERIMENTAL DESIGN: We explored whether distinct prognostic features, common to all breast cancer molecular subtypes, exist in postpartum tumor tissue. Using detailed breastfeeding data, we delineated the postweaning period in PP-BC as a surrogate for mammary gland involution and performed whole transcriptome sequencing, immunohistochemical, and (multiplex) immunofluorescent analyses on tumor tissue of patients with PP-BCPW, PP-BCDL, Pr-BC, and NP-BC. RESULTS: We found that patients with PP-BCPW having a low expression level of an immunoglobulin gene signature, but high infiltration of plasma B cells, have an increased risk for metastasis and death. Although PP-BCPW tumor tissue was also characterized by an increase in CD8+ cytotoxic T cells and reduced distance among these cell types, these parameters were not associated with differential clinical outcomes among groups. CONCLUSIONS: These data point to the importance of plasma B cells in the postweaning mammary tumor microenvironment regarding the poor prognosis of PP-BCPW patients. Future prospective and in-depth research needs to further explore the role of B-cell immunobiology in this specific group of young patients with breast cancer.

Outcome of breast cancer patients treated with chemotherapy during pregnancy compared with non-pregnant controls.

BACKGROUND: A diagnosis of breast cancer during pregnancy (PrBC) does not impact prognosis if standard treatment is offered. However, caution is warranted as gestational changes in pharmacokinetics may lead to reduced chemotherapy concentration. METHODS: Survival of PrBC patients treated with chemotherapy during pregnancy was compared to non-pregnant breast cancer patients treated with chemotherapy, diagnosed after 2000, excluding patients older than 45 years or with a postpartum diagnosis. The data was registered in two multicenter registries (the International Network of Cancer, Infertility and Pregnancy and the German Breast Group). Cox proportional hazards regression was used to compare disease-free (DFS) and overall survival (OS) between both groups, adjusting for age, stage, grade, hormone receptor status, human epidermal growth factor 2 status and histology, weighted by propensity scoring to account for the differences in baseline characteristics between pregnant patients and controls. RESULTS: In total, 662 pregnant and 2081 non-pregnant patients were selected. Pregnant patients were more likely to have stage II breast cancer (60.1% vs 56.1%, p = 0.035), grade 3 tumors (74.0% vs 62.2%, p < 0.001), hormone receptor-negative tumors (48.4% vs 34.0%, p < 0.001) or triple-negative breast cancer (38.9% vs 26.9%, p < 0.001). Median follow-up was 66 months. In multivariable analysis, DFS and OS were comparable for pregnant and non-pregnant patients (DFS: HR 1.02, 95% CI 0.82-1.27, p = 0.83; OS: HR 1.08, 95% CI 0.81-1.45, p = 0.59). CONCLUSION: Outcome of women with breast cancer treated with chemotherapy during pregnancy is comparable to young non-pregnant women. These results support chemotherapy for PrBC when indicated.

Data describing the poor outcome associated with a breast cancer diagnosis in the post-weaning period.

Postpartum breast cancer (PPBC) - which according to new data, can extend to 5-10 years after the birth - are estimated to represent 35-55% of all cases of breast cancer in women younger than 45 years. Increasing clinical evidence indicates that PPBC represents a high-risk form of breast cancer in young women with an approximately 2-fold increased risk for metastasis and death. Yet, the exact mechanisms that underlay this poor prognosis are incompletely understood and, hence, it is unknown why postpartum breast cancer has an enhanced risk for metastasis or how it should be effectively targeted for improved survival. This article is an accompanying resource of the original article entitled "Breast cancer diagnosed in the post-weaning period is indicative for a poor outcome" and present epidemiological data that compare standard prognostic parameters, first site of metastatic disease and survival and metastatic rates in young women with primary invasive breast cancer diagnosed within two years postpartum (PP-BC), in young women diagnosed during pregnancy (Pr-BC) and nulliparous women (NP-BC). Via an international collaboration of 13 centres participating in the International Network on Cancer, Infertility and Pregnancy (INCIP), retrospective data of 1180 patients with primary invasive breast cancer, aged 25-40 years and diagnosed between January 1995 and December 2017 were collected. In particular, tumour-, patient, and therapy-related characteristics were collected. Furthermore, patient files were reviewed thoroughly to assess, for each parity, if and for how long breastfeeding was given. For PP-BC patients, breastfeeding history was used to differentiate breast cancers identified during lactation (PP-BCDL) from those diagnosed post-weaning (PP-BCPW). Primary exposures were prior childbirth or no childbirth, time between most recent childbirth and breast cancer diagnosis, time between cessation of lactation and breast cancer diagnosis and time between breast cancer diagnosis and metastasis or death. Distribution of standard prognostic parameters and first site of distant metastasis among study groups was determined applying fisher's exact, chi-squared, One-Way ANOVA or Kruskal-Wallis tests or logistic regression models, where applicable. The risks for metastasis and death were assessed using Cox proportional hazards models. A subgroup analysis was performed in PP-BCPW patients that never lactated (PP-BCPW/NL), lactated ≤3 months (PP-BCPW/Lshort) or lactated >3 months (PP-BCPW/Llong).

Breast cancer diagnosed in the post-weaning period is indicative for a poor outcome.

BACKGROUND: In young women, a breast cancer diagnosis after childbirth increases the risk for metastasis and death. Studies in rodents suggest that post-weaning mammary gland involution contributes to the poor prognosis of postpartum breast cancers. However, this association has not been investigated in humans, mainly because of missing information on the patient's lactation status at diagnosis. PATIENTS AND METHODS: Clinicopathological data of 1180 young women with primary invasive breast cancer, diagnosed within 2 years postpartum (PP-BC), during pregnancy (Pr-BC), or nulliparous (NP-BC), were collected. For PP-BC patients, breastfeeding history was retrieved to differentiate breast cancers identified during lactation (PP-BCDL) from those diagnosed post-weaning (PP-BCPW). Differences in prognostic parameters, first site of distant metastasis, and risks for metastasis and death were determined between patient groups. RESULTS: Cox proportional hazard models pointed to a twofold increased the risk of metastasis and death in PP-BCPW patients compared with PP-BCDL (hazard ratio [HR] 2.1 [PDRS = 0.021] and 2.9 [POS = 0.004]), Pr-BC (HR 2.1 [PDRS<0.001] and 2.3 [POS<0.001]) and NP-BC (HR 2.1 [PDRS<0.001] and 2.0 [POS<0.001]) patients. Prognosis was poorest for PP-BCPW patients who did not breastfeed or only for ≤ 3 months before diagnosis. This could not fully be attributed to differences in standard prognostic characteristics. In addition, PP-BCPW tumours showed a 3- to 8-fold increased risk to metastasise to the liver, yet this did not correlate with the poor outcome of this patient cohort. CONCLUSIONS: Breast cancer diagnosed shortly after weaning specifically adds to the poor prognosis in women diagnosed with PP-BC. Apart from the importance of an increased awareness, these data show that detailed lactation data need to be registered when breast cancer outcome in young women is investigated.

The MNK1/2-eIF4E Axis Supports Immune Suppression and Metastasis in Postpartum Breast Cancer.

Breast cancer diagnosed within 10 years following childbirth is defined as postpartum breast cancer (PPBC) and is highly metastatic. Interactions between immune cells and other stromal cells within the involuting mammary gland are fundamental in facilitating an aggressive tumor phenotype. The MNK1/2-eIF4E axis promotes translation of prometastatic mRNAs in tumor cells, but its role in modulating the function of nontumor cells in the PPBC microenvironment has not been explored. Here, we used a combination of in vivo PPBC models and in vitro assays to study the effects of inactivation of the MNK1/2-eIF4E axis on the protumor function of select cells of the tumor microenvironment. PPBC mice deficient for phospho-eIF4E (eIF4ES209A) were protected against lung metastasis and exhibited differences in the tumor and lung immune microenvironment compared with wild-type mice. Moreover, the expression of fibroblast-derived IL33, an alarmin known to induce invasion, was repressed upon MNK1/2-eIF4E axis inhibition. Imaging mass cytometry on PPBC and non-PPBC patient samples indicated that human PPBC contains phospho-eIF4E high-expressing tumor cells and CD8+ T cells displaying markers of an activated dysfunctional phenotype. Finally, inhibition of MNK1/2 combined with anti-PD-1 therapy blocked lung metastasis of PPBC. These findings implicate the involvement of the MNK1/2-eIF4E axis during PPBC metastasis and suggest a promising immunomodulatory route to enhance the efficacy of immunotherapy by blocking phospho-eIF4E. SIGNIFICANCE: This study investigates the MNK1/2-eIF4E signaling axis in tumor and stromal cells in metastatic breast cancer and reveals that MNK1/2 inhibition suppresses metastasis and sensitizes tumors to anti-PD-1 immunotherapy.

MNK1/NODAL Signaling Promotes Invasive Progression of Breast Ductal Carcinoma In Situ.

The mechanisms by which breast cancers progress from relatively indolent ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) are not well understood. However, this process is critical to the acquisition of metastatic potential. MAPK-interacting serine/threonine-protein kinase 1 (MNK1) signaling can promote cell invasion. NODAL, a morphogen essential for embryogenic patterning, is often reexpressed in breast cancer. Here we describe a MNK1/NODAL signaling axis that promotes DCIS progression to IDC. We generated MNK1 knockout (KO) or constitutively active MNK1 (caMNK1)-expressing human MCF-10A-derived DCIS cell lines, which were orthotopically injected into the mammary glands of mice. Loss of MNK1 repressed NODAL expression, inhibited DCIS to IDC conversion, and decreased tumor relapse and metastasis. Conversely, caMNK1 induced NODAL expression and promoted IDC. The MNK1/NODAL axis promoted cancer stem cell properties and invasion in vitro. The MNK1/2 inhibitor SEL201 blocked DCIS progression to invasive disease in vivo. In clinical samples, IDC and DCIS with microinvasion expressed higher levels of phospho-MNK1 and NODAL versus low-grade (invasion-free) DCIS. Cumulatively, our data support further development of MNK1 inhibitors as therapeutics for preventing invasive disease. SIGNIFICANCE: These findings provide new mechanistic insight into progression of ductal carcinoma and support clinical application of MNK1 inhibitors to delay progression of indolent ductal carcinoma in situ to invasive ductal carcinoma.

Modular approach to customise sample preparation procedures for viral metagenomics: a reproducible protocol for virome analysis.

A major limitation for better understanding the role of the human gut virome in health and disease is the lack of validated methods that allow high throughput virome analysis. To overcome this, we evaluated the quantitative effect of homogenisation, centrifugation, filtration, chloroform treatment and random amplification on a mock-virome (containing nine highly diverse viruses) and a bacterial mock-community (containing four faecal bacterial species) using quantitative PCR and next-generation sequencing. This resulted in an optimised protocol that was able to recover all viruses present in the mock-virome and strongly alters the ratio of viral versus bacterial and 16S rRNA genetic material in favour of viruses (from 43.2% to 96.7% viral reads and from 47.6% to 0.19% bacterial reads). Furthermore, our study indicated that most of the currently used virome protocols, using small filter pores and/or stringent centrifugation conditions may have largely overlooked large viruses present in viromes. We propose NetoVIR (Novel enrichment technique of VIRomes), which allows for a fast, reproducible and high throughput sample preparation for viral metagenomics studies, introducing minimal bias. This procedure is optimised mainly for faecal samples, but with appropriate concentration steps can also be used for other sample types with lower initial viral loads.