Lymph Vessels Associate with Cancer Stem Cells from Initiation to Malignant Stages of Squamous Cell Carcinoma

Tumor-associated lymph vessels and lymph node involvement are critical staging criteria in several cancers. In skin squamous cell carcinoma, lymph vessels play a role in cancer development and metastatic spread. However, their relationship with the cancer stem cell niche at early tumor stages remains unclear. To address this gap, we studied the lymph vessel localization at the cancer stem cell niche and observed an association from benign skin lesions to malignant stages of skin squamous cell carcinoma. By co-culturing lymphatic endothelial cells with cancer cell lines representing the initiation and promotion stages, and conducting RNA profiling, we observed a reciprocal induction of cell adhesion, immunity regulation, and vessel remodeling genes, suggesting dynamic interactions between lymphatic and cancer cells. Additionally, imaging analyses of the cultured cells revealed the establishment of heterotypic contacts between cancer cells and lymph endothelial cells, potentially contributing to the observed distribution and maintenance at the cancer stem cell niche, inducing downstream cellular responses. Our data provide evidence for an association of lymph vessels from the early stages of skin squamous cell carcinoma development, opening new avenues for better comprehending their involvement in cancer progression.

Hematopoietic Stem Cell (HSC)-Independent Progenitors Are Susceptible to Mll-Af9-Induced Leukemic Transformation

Infant acute myeloid leukemia (AML) is a heterogeneous disease, genetically distinct from its adult counterpart. Chromosomal translocations involving the KMT2A gene (MLL) are especially common in affected infants of less than 1 year of age, and are associated with a dismal prognosis. While these rearrangements are likely to arise in utero, the cell of origin has not been conclusively identified. This knowledge could lead to a better understanding of the biology of the disease and support the identification of new therapeutic vulnerabilities. Over the last few years, important progress in understanding the dynamics of fetal hematopoiesis has been made. Several reports have highlighted how hematopoietic stem cells (HSC) provide little contribution to fetal hematopoiesis, which is instead largely sustained by HSC-independent progenitors. Here, we used conditional Cre-Lox transgenic mouse models to engineer the Mll-Af9 translocation in defined subsets of embryonic hematopoietic progenitors. We show that embryonic hematopoiesis is generally permissive for Mll-Af9-induced leukemic transformation. Surprisingly, the selective introduction of Mll-Af9 in HSC-independent progenitors generated a transplantable myeloid leukemia, whereas it did not when introduced in embryonic HSC-derived cells. Ex vivo engineering of the Mll-Af9 rearrangement in HSC-independent progenitors using a CRISPR/Cas9-based approach resulted in the activation of an aberrant myeloid-biased self-renewal program. Overall, our results demonstrate that HSC-independent hematopoietic progenitors represent a permissive environment for Mll-Af9-induced leukemic transformation, and can likely act as cells of origin of infant AML.

Human SLFN5 and its Xenopus Laevis ortholog regulate entry into mitosis and oocyte meiotic resumption

The Schlafen gene family was first described in mice as a regulator of thymocyte development. Further studies showed involvement of human orthologs in different processes related with viral replication, cellular proliferation, and differentiation. In recent years, a new role for human Slfn11 in DNA replication and chromatin remodeling was described. As commonly observed in many gene families, Slfn paralogs show a tissue-specific expression. This made it difficult to reach conclusions which can be valid in different biological models regarding the function of the different Schlafen proteins. In the present study, we investigate the involvement of SLFN5 in cell-cycle regulation and cell proliferation. A careful analysis of SLFN5 expression revealed that SLFN5 is highly expressed in proliferating tissues and that the protein is ubiquitously present in all the tissues and cell line models we analyzed. Very interestingly, SLFN5 expression oscillates during cell cycle, peaking during S phase. The fact that SLFN5 interacts with protein phosphatase 2A and that SLFN5 depletion causes cell cycle arrest and cellular apoptosis, suggests a direct involvement of this human paralog in cell cycle progression and cellular proliferation. We substantiated our in vitro and in cellulo results using Xenopus laevis oocytes to show that mRNA depletion of the unique Slfn gene present in Xenopus, whose protein sequence shares 80% of homology with SLFN5, recapitulates the phenotype observed in human cells preventing the resumption of meiosis during oocyte development.

Prenatal Origin of Pediatric Leukemia: Lessons From Hematopoietic Development

Several lines of evidence suggest that childhood leukemia, the most common cancer in young age, originates during in utero development. However, our knowledge of the cellular origin of this large and heterogeneous group of malignancies is still incomplete. The identification and characterization of their cell of origin is of crucial importance in order to define the processes that initiate and sustain disease progression, to refine faithful animal models and to identify novel therapeutic approaches. During embryogenesis, hematopoiesis takes place at different anatomical sites in sequential waves, and occurs in both a hematopoietic stem cell (HSC)-dependent and a HSC-independent fashion. Despite the recently described relevance and complexity of HSC-independent hematopoiesis, few studies have so far investigated its potential involvement in leukemogenesis. Here, we review the current knowledge on prenatal origin of leukemias in the context of recent insights in developmental hematopoiesis.

TP53 deficiency permits chromosome abnormalities and karyotype heterogeneity in acute myeloid leukemia

Abnormal karyotypes are common in cancer cells and frequently observed in acute myeloid leukemia (AML), in which complex karyotype aberrations are associated with poor prognosis. How exactly abnormal karyotypes arise and are propagated in AML is unclear. TP53 mutations and deletions are frequent in complex karyotype AML, suggesting a role of TP53 alterations in the development of chromosome abnormalities. Here, we generated isogenic TP53-knockout versions of the euploid AML cell line EEB to investigate the impact of TP53 on karyotype stability. We show that chromosome abnormalities spontaneously arise in TP53-deficient cells. Numerical aneuploidy could, to some extent, be propagated in a TP53-proficient setting, indicating that it does not necessarily trigger TP53 activation. In contrast, tolerance to structural chromosome aberrations was almost entirely restricted to TP53-knockout clones, all of which were able to continue proliferation in the presence of damaged DNA. Mechanistically, as a source of chromosome aberrations, limited numerical but not structural chromosomal instability was tolerated by TP53-wildtype cells. In contrast, structural instability was found only in TP53-knockout cells. Together, in myeloid cells TP53 loss allows for the development of complex karyotype aberrations and karyotype heterogeneity by perpetuation of chromosome segregation errors.

Chemotherapy-induced tumor necrosis as a prognostic factor in localized Ewing's sarcoma of the extremities

PURPOSE

This study was performed to assess the prognostic value of the proposed histopathologic method to evaluate the response of the primary tumor to preoperative chemotherapy in Ewing's sarcoma.

PATIENTS AND METHODS

The response to chemotherapy was evaluated from the specimens of 118 Ewing's sarcoma patients, who were preoperatively treated by chemotherapy alone. Responses were graded I to III (macroscopic viable tumor, microscopic viable tumor, and no viable tumor cells, respectively). Follow-up data were available for all patients, with a mean follow-up duration of 86 months (range, 30 to 158).

RESULTS

A statistically highly significant difference was observed in outcome among the three groups of patients. For patients with total necrosis (grade III response), the estimated 5-year disease-free survival rate was 95%, in contrast to 68% for grade II responders and 34% for grade III responders (P < .0001). This difference was also confirmed when any single group was compared with the other groups. Among the parameters tested, patient age and the size of tumor had some prognostic value.

CONCLUSION

The proposed histopathologic grading, to evaluate the effect of chemotherapy on the primary tumor, had the strongest correlation to clinical outcome. This method could therefore be used to identify patients with a high risk of recurrent disease. These patients could be randomized to receive alternative postoperative treatments to investigate whether more aggressive therapies will improve outcome.

Methotrexate serum concentration and histological response to multiagent primary chemotherapy for osteosarcoma of the limbs

The authors investigated the influence of methotrexate (MTX) serum concentration on (histologically evaluated) tumor necrosis, induced by a primary multiagent chemotherapy, including MTX, for osteosarcoma. MTX serum peaks in 151 patients, preoperatively treated with MTX (8-12g/m2), cisplatin (120mg/m2) and Adriamycin (60mg/m2), were analyzed. Significantly (p < 0.01) higher serum MTX mean peaks were observed in patients with complete tumor necrosis (MTX 773.8 mumol/l) compared to patients with 90-99% tumor necrosis (639.8 mumol/l), 50-89% tumor necrosis (649.1 mumol/l) or less than 50% tumor necrosis (610 mumol/l). Complete tumor necrosis was observed in 9% of patients with MTX peaks of less than 600 mumol/l, in 27% of patients with serum MTX peaks between 600 and 699 mumol/l and in 37% of those with MTX peaks ranging from 700 to 799 mumol/l. Higher MTX peaks (800-899, 900-999, > 1000 mumol/l) were not associated with a further increase of cases with complete tumor necrosis. 40% of patients with an MTX peak greater than 700 mumol/l had complete tumor necrosis, compared to 15.5% of patients who did not reach this value (p < 0.002). At a multivariant analysis including age, sex, tumor site and volume, pretreatment serum alkaline phosphatase and lactic dehydrogenase levels, MTX peaks of 700 mumol/l and, less significantly, the histologic type (telangiectatic osteosarcoma), were independent factors influencing tumor necrosis. The authors conclude that MTX serum peaks significantly influence chemotherapy-induced tumor necrosis in osteosarcoma. In a primary treatment consisting of cisplatin, Adriamycin and MTX, complete tumor necrosis can be obtained in 40% of patients with MTX peak concentrations > or = 700 mumol/l.

A profile of the female cycle length

"This study suggests some points of view about the menstrual cycle length. In the first part aggregate indicators of cycle characteristics are computed for various types of data aggregations.... In the second part, the period analysis and the consequent estimated spectral density functions are applied to the basal body temperature series." Data are for 1,798 women in London, England. (SUMMARY IN ITA)

Complications and surgical indications in 144 cases of nonmetastatic osteosarcoma of the extremities treated with neoadjuvant chemotherapy

From September 1986 to December 1989, 144 patients with osteosarcoma of the extremities were treated with combined surgery and neoadjuvant chemotherapy. The disease-free survival was 79% for good responders (necrosis greater than 90%) and 72% for poor responders (necrosis less than 90%), and the local recurrence rate was low. Improvement in long-term prognosis and the increase of limb-sparing surgery determine a higher rate of immediate and late complications. Most of the complications were observed in limb-salvage procedures; 63% of these procedures presented one or more complications. In nine rotationsplasties, there were four complications, and in 13 amputations no complications were observed. Therefore, 55% of patients were affected by surgical complications. Twenty-eight complications were considered minor (not requiring surgery), whereas 77 complications were major. Functional results, evaluated according to Enneking's new system, were higher than 50% in two thirds of the limb-salvage procedures. Complications in limb-salvage procedures are more influenced by the type of reconstruction than by the surgical procedure used. Probably the most troublesome consequence of surgical complications in osteosarcoma is the deviation or delay in administering postoperative chemotherapy, which jeopardizes survival.

Prognostic significance of histopathologic response to chemotherapy in nonmetastatic Ewing's sarcoma of the extremities

PURPOSE

To evaluate more accurately the effectiveness of preoperative chemotherapy in the treatment of patients with Ewing's sarcoma, we studied histopathologically the chemotherapeutic response and correlated it to oncologic outcome.

PATIENTS AND METHODS

Between June 1983 and December 1989, 68 patients with nonmetastatic Ewing's sarcoma of the extremities were treated at our institute with preoperative chemotherapy (without radiation therapy) and surgery. The specimens were retrospectively evaluated for areas of viable tumor cells and graded from I to III (macroscopic, microscopic, or no residual disease, respectively) in a blinded fashion. Clinical follow-up data were available on all patients for a mean of 60 months (range, 32 to 111).

RESULTS

This histopathologic analysis was strongly correlated with oncologic outcome (P = .004). Patients who demonstrated grade III response (no identifiable viable tumor nodules present) had improved 5-year disease-free survival rates as compared with patients with grade II (microscopic nodes present; P = .023; 90% v 53%) and grade I responses (macroscopic nodules present; P = .0003; 90% v 32%). Patients with grade II necrosis had statistically improved survival rates over those with grade I necrosis (53% v 32%; P = .074).

CONCLUSION

This new histopathologic analysis technique for the evaluation of neoadjuvant chemotherapy effectiveness (which does not rely on tumor volume for its assessment) is a valuable prognostic indicator for patients with Ewing's sarcoma treated with surgery. Based on this preliminary report, cases of grade I or II chemotherapeutic tumor response should be considered clinical failures and a different, more aggressive postoperative chemotherapy regimen should be considered.

Influence of chemotherapy on perioperative complications in limb salvage surgery for bone tumors

From 1970 to 1986, 304 patients underwent limb salvage resections for 271 malignant and 33 benign tumors of the extremities. Reconstruction was with a prosthesis or nonbiologic spacer. Nonmechanical complications were analyzed to determine the influence of the site and method of reconstruction and the use of chemotherapy on their incidence and severity. There were 82 shoulder resections, 53 proximal femur resections, and 169 knee resections. No chemotherapy was used in 115 patients; neoadjuvant therapy was used in 128 patients and adjuvant therapy was used in 61. There were 120 complications. The most common complication was infection (36 of 304 patients; 11.8%), which led to amputation in eight patients. Resections about the knee led to more complications than the other sites, particularly if reconstructed with a large cement spacer. Patients who did not receive any chemotherapy had a 25.2% (29 of 115) incidence of complications and those who received adjuvant treatment had a 32.8% (20 of 61) incidence. This compares with a 55.4% (71 of 128) incidence in the neoadjuvant group. After neoadjuvant chemotherapy, reconstruction with an uncemented prosthesis led to the fewest complications.

Effect of perioperative transfusions on survival in osteosarcoma treated by multimodal therapy

We report on a retrospective study of 155 patients amputated for nonmetastatic osteosarcoma of the long bones. Among the various prognostic variables considered, a significant correlation was found only between survival and transfusions. In this report, the authors consider some hypotheses reported by others for tumors of a different nature and site and conclude that perioperative transfusion may induce depression in the immune response, which is the cause of a shorter survival in the patients reviewed.