[A Case of Lynch Syndrome with Seven Cancers in Five Organs].

The case is a woman in her 70s with a history of colon and cervical cancer in her 40s. She had gastric cancer and breast cancer in her 70s. Her eldest son died of colon cancer in his 20s, and her eldest daughter had cervical cancer in her 40s. She was suspected to have Lynch syndrome and a genetic diagnosis was performed and then confirmed. Later she developed gastric cancer and ureteral cancer. We report a case of Lynch syndrome in which she developed seven cancers in five organs, all of which were early stage cancers.

Influence of aldo-keto reductase 1C3 polymorphisms in early-onset female psoriasis patients.

The principal pathology of psoriasis is impaired skin barrier function, epidermal thickening, and granular layer loss. Exposure to extrinsic factors such as tobacco smoke and air pollutants is associated with the development of psoriasis. Aryl hydrocarbon receptors (AHRs) are activated by extrinsic factors associated with the development of psoriasis and act as transcriptional regulators. Expression of aldo-keto reductase (AKR) 1C3 in the epidermal spinous layer regulates epidermal keratinocyte differentiation via the AHR signaling pathway. We investigated whether single nucleotide polymorphisms (SNPs) in AKR1C3 are associated with the pathogenesis of psoriasis. The proportions of rs12529 G/C, C/C variants, and rs12387 A/A, A/G variants were twofold higher in Japanese psoriasis patients (n = 231) compared with a Japanese healthy cohort. The SNPs were significantly more common than the majority variants in female patients with disease onset ≤ 22 years of age. Patients with rs12529 G > C and rs12387 A > G SNPs exhibited significantly lower AKR1C3 expression and higher expression of late differentiation markers. In conclusion, AKR1C3 downregulation caused by rs12529 G > C and rs12387 A > G SNPs in the epidermis induces abnormal early differentiation of keratinocytes and skin barrier dysfunction, which may contribute to the genetic pathogenesis of psoriasis in young females.

Inflammatory Myofibroblastic Tumor in the Adrenal Gland: A Case Report.

Inflammatory myofibroblastic tumors (IMTs) were first described by Harold Brunn in 1939. IMTs are mainly found in the lungs and other sites of the body; hence, its occurrence in the adrenal gland is exceptional. In the literature, less than 10 cases of IMTs in the adrenal gland have been reported. The etiology of IMT remains unknown, with post-inflammatory changes and a neoplastic origin being proposed. We present a case of a 19-year-old woman and adrenal gland IMT. The patient presented with abdominal pain and low cardiac output without hypovolemic shock. Computed tomography revealed a tumor in the adrenal gland measuring 11.4 cm with extravasation of contrast medium within the tumor. Treatment included conservative management with selective embolization due to minimal invasion of the inferior artery of the adrenal gland. The patient was then discharged with possibility of future elective surgery. Four months later, the size of the tumor decreased to 6.3 cm, and her Eastern Cooperative Oncology Group physical status was 0. The Multidisciplinary Tumor Board suggested surgical management. The final histopathology report was compatible with an IMT of the adrenal gland, with the immunohistochemical report showing positivity for anti-actin muscle-specific and anti-actin smooth muscle and negativity for anaplastic lymphoma kinase. IMTs of the adrenal gland may be treated electively through multidisciplinary management together with interventional radiology and surgery, achieving a favorable outcome for the patient.

Clinical utility of comprehensive genomic profiling in Japan: Result of PROFILE-F study.

INTRODUCTION: Clinical sequencing has provided molecular and therapeutic insights into the field of clinical oncology. However, despite its significance, its clinical utility in Japanese patients remains unknown. Here, we examined the clinical utility of tissue-based clinical sequencing with FoundationOne® CDx and FoundationOne® Heme. Between August 2018 and August 2019, 130 Japanese pretreated patients with advanced solid tumors were tested with FoundationOne® CDx or FoundationOne® Heme. RESULTS: The median age of 130 patients was 60.5 years (range: 3 to 84 years), and among them, 64 were males and 66 were females. Major cancer types were gastrointestinal cancer (23 cases) and hepatic, biliary, and pancreatic cancer (21 cases). A molecular tumor board had been completed on all 130 cases by October 31, 2019. The median number of gene alterations detected by Foundation testing, excluding variants of unknown significance (VUS) was 4 (ranged 0 to 21) per case. Of the 130 cases, one or more alterations were found in 123 cases (94.6%), and in 114 cases (87.7%), actionable alterations with candidates for therapeutic agents were found. In 29 (22.3%) of them, treatment corresponding to the gene alteration was performed. Regarding secondary findings, 13 cases (10%) had an alteration suspected of a hereditary tumor. Of the 13 cases, only one case received a definite diagnosis of hereditary tumor. CONCLUSIONS: Our study showed that clinical sequencing might be useful for detecting gene alterations in various cancer types and exploring treatment options. However, many issues still need to be improved.

Association between Cerebral Infarction Risk and Medication Adherence in Atrial Fibrillation Patients Taking Direct Oral Anticoagulants.

Direct oral anticoagulants (DOACs) are available for nonvalvular atrial fibrillation patients. The advantage of DOACs is that regular anticoagulation monitoring is not required. However, adherence to the recommended regimen is essential. We investigated the association between medication adherence and the risk of cerebral infarction in patients taking DOACs. Patients admitted to any of the participating hospitals for cerebral infarction from September 2018 to February 2020 and prescribed DOACs before admission were defined as the case group, and patients hospitalized for diseases other than cerebral infarction, except for bleeding disorders, and prescribed DOACs before admission were defined as the control group. A nested case-control study was adapted, and 58 and 232 patients were included in the case and control groups, respectively. Medication adherence was assessed by the pharmacists through standardized interviewing. The adjusted odds ratio for the risk of cerebral infarction for low-adherence patients (<80% adherence rate) against good-adherence patients (100% adherence rate) was 9.69 (95% confidence interval, 3.86-24.3; p < 0.001). The patients' age and other background characteristics were not found to be risk factors for cerebral infarction. In conclusion, low adherence is a risk factor for cerebral infarction in patients taking DOACs. Pharmacists should focus on maintaining ≥80% adherence to DOAC therapy to prevent cerebral infarction.

Large leiomyomatosis peritonealis disseminata after laparoscopic myomectomy: A case report with literature review.

INTRODUCTION: Leiomyomatosis peritonealis disseminata (LPD) is a rare disease in which multiple leiomyomas are formed intraperitoneally. Several LPD cases were associated with laparoscopic myomectomy using power morcellators; however, LPD with a large tumor size remains extremely rare. We present a case of large LPD occurring after laparoscopic surgery. PRESENTATION OF CASE: A 26-year-old woman, gravida 0, underwent laparoscopic myomectomy with power morcellation in our institution. After 5 years, follow-up examination revealed pelvic tumors. Although we recommended resection, she refused and only wanted to be followed up. After 9 years from the first surgery, the tumors became symptomatic and were increasing in number (>10 nodules) and size (>15 cm). Needle biopsy detected leiomyoma. Computed tomography angiography showed that omental and mesenteric arteries were feeding the tumors. We performed laparotomy, and all the 19 tumors emerging from the omentum and mesenterium and weighing 7647 g in total were removed without injuring other organs. The maximum diameter of the largest tumor was 34 cm. The pathological diagnosis was nonmalignant LPD with leiomyoma. DISCUSSION: Among all reported cases, our case had the largest LPD size. The tumors reached such a huge size because of two possible reasons: (1) they gradually grew asymptomatically over a long period from the time of diagnosis, and (2) they were fed by particularly large vessels, including the omental and mesenteric arteries. CONCLUSION: A large LPD is not always symptomatic. After a laparoscopic myomectomy, especially with power morcellation, long-term follow-up is necessary to detect LPD.

Acute mesenteric thrombosis in two patients with COVID-19. Two cases report and literature review.

INTRODUCTION: The coronavirus disease 2019 (COVID-19) affects mainly the respiratory system, other organs may be involved, usually due to coagulation disturbances that lead to a high rate of thrombotic complications. CASE PRESENTATION: The first patient is 45 years-old who has been exposed to SARS CoV-2. Upon admission due to acute abdomen evidence surgery is performed in which an intestinal resection with an adequate post-surgical evolution takes place so the patient is discharged after 4 days with a prescription for oral anticoagulants. The second one is 42 years-old and has comorbidities. The patient is admitted upon evidence of COVID-19, after showing signs of vein mesenteric ischemia in a CT scan surgery is performed, however the patient dies 24 h after the intervention. DISCUSSION: Within severe cases of patients with COVID-19 the incidence of a symptomatology or gastrointestinal complications is high (39-73.8%). Thromboprophylaxis is recommended to all patients admitted for COVID-19, starting with heparin of low molecular weight as prophylaxis, as well as continuing with oral anticoagulants after being discharged. CONCLUSION: Despite the fact that knowledge of the disease is rapidly advancing, all available treatments are still nonspecific to SARS-CoV-2 and the optimal management of COVID-19 remains unclear. An unexplained clinical picture should raise the suspicion for rare conditions such as mesenteric thrombosis. Adequate prophylactic measures should be implemented both during hospitalization and after discharge.

Lipocalin-type prostaglandin D synthase regulates light-induced phase advance of the central circadian rhythm in mice.

We previously showed that mice lacking pituitary adenylate cyclase-activating polypeptide (PACAP) exhibit attenuated light-induced phase shift. To explore the underlying mechanisms, we performed gene expression analysis of laser capture microdissected suprachiasmatic nuclei (SCNs) and found that lipocalin-type prostaglandin (PG) D synthase (L-PGDS) is involved in the impaired response to light stimulation in the late subjective night in PACAP-deficient mice. L-PGDS-deficient mice also showed impaired light-induced phase advance, but normal phase delay and nonvisual light responses. Then, we examined the receptors involved in the response and observed that mice deficient for type 2 PGD2 receptor DP2/CRTH2 (chemoattractant receptor homologous molecule expressed on Th2 cells) show impaired light-induced phase advance. Concordant results were observed using the selective DP2/CRTH2 antagonist CAY10471. These results indicate that L-PGDS is involved in a mechanism of light-induced phase advance via DP2/CRTH2 signaling.

Effect of dietary medium-chain triacylglycerol on serum albumin and nitrogen balance in malnourished rats.

The present study was examined the therapeutic effect of medium-chain triacylglycerol (MCT) in protein-energy malnutrition (PEM). Wistar rats were fed low protein diet containing 70 g/kg of long-chain triacylglycerol (LCT) or MCT for 31 days. The serum albumin concentration in rats fed MCT diet (2.88 +/- 0.04 g/dl) were significantly higher compared with those fed LCT diet (2.72 +/- 0.04 g/dl) at day 31. Nitrogen balance was higher in rats fed MCT diet (54.1 +/- 2.3 mg/day) compared with those fed LCT diet (45.4 +/- 2.4 mg/day) during d 10-12. These results suggest that MCT effectively elevates serum albumin concentration and improves nitrogen balance in malnourished rats.

Splenic PGE2-releasing macrophages regulate Th1 and Th2 immune responses in mice treated with heat-killed BCG.

Hosts infected with low doses of mycobacteria develop T helper cell type 1 (Th1) immunity, but at relatively higher doses, a switch to Th2 immunity occurs. Prostaglandin E2 (PGE2) is a proposed mediator of the Th1-to-Th2 shift of immune responses, and mycobacterial products induce PGE2-releasing macrophages (PGE2-MØ) in the mouse spleen in a dose-dependent manner. Splenic PGE2-M Ø from Balb/c mice, given 0.01 or 1 mg heat-killed (HK) Mycobacterium bovis bacillus Calmette-Guerin (BCG) intraperitoneally (i.p.), were characterized by the ex vivo release of PGE2 (>10 ng/10(6) cells), cytokine production, and expression of PGG/H synthase (PGHS)-1, PGHS-2, cytosolic PGE synthase (PGES), and microsomal PGES-1. At Day 14 after the treatment, mice treated with 1 mg, but not 0.01 mg, BCG had increased levels of PGHS-2+ PGE2-MØ, total serum immunoglobulin E (IgE), and serum IgG1 antibodies (Th2 responses) against heat shock protein 65 and purified protein derivative. Cultures of spleen cells isolated from these mice expressed interleukin (IL)-4 and IL-10 in recall responses. Treatment of mice receiving 1 mg BCG with NS-398 (a PGHS-2 inhibitor, 10 mg/kg i.p., daily) resulted in enhanced interferon-gamma (IFN-gamma) production with reduced IL-4 and IL-10 production in recall responses. This treatment also resulted in decreased total serum IgE levels. Treatment of C57Bl/6 mice with HK-BCG (0.5 mg dose) also induced a mixture of Th1 and Th2 responses, although IFN-gamma production was markedly increased, and IL-4 was decreased compared with Balb/c mice. Thus, our results indicate that by 14 days following treatment of mice with high doses of HK-BCG, splenic PGE2-MØ formation is associated with a PGHS-2-dependent shift from Th1-to-Th2 immune responses.

A Report on Nursing Information During Volunteer Activities Conducted by Nursing Faculty Members and Students After the Great East Japan Earthquake.

A survey was conducted about nursing information in volunteer activities of nursing faculty members and students after the Great East Japan Earthquake. Results indicated that it was important to attempt collecting information in every possible way and to always be prepared. During activities, it is important to record information, to share information with individuals other than nursing professionals and to make good use of it.

Effect of 2 weeks' consumption of pomegranate juice on the pharmacokinetics of a single dose of midazolam: an open-label, randomized, single-center, 2-period crossover study in healthy Japanese volunteers.

BACKGROUND: It has been reported that pomegranate juice significantly increased the AUC of orally administered carbamazepine in rats, which suggests that pomegranate may inhibit the cytochrome P450 3A (CYP3A)-mediated carbamazepine metabolism. OBJECTIVE: The aim of the present study was to clarify the effect of repeated consumption of pomegranate juice on CYP3A activity by assessing the pharmacokinetics of midazolam, a typical CYP3A probe drug, and its metabolites in healthy volunteers. METHODS: An open-label, randomized, single-center, 2-period crossover study was conducted on healthy Japanese volunteers. Each subject received 200 mL of pomegranate juice twice daily for 2 weeks. On day 14, they were administered 15 µg/kg midazolam orally with either pomegranate juice or water. Plasma concentrations and urinary excretions of midazolam, 1'-hydroxymidazolam, and 4-hydroxymidazolam were determined up to 24 hours using LC/MS/MS and analyzed by a noncompartmental method. RESULTS: Sixteen subjects (11 men and 5 women) were enrolled and completed the study. The mean (SD) age was 24.1 (4.8) years (range 22-40), mean body weight was 62.9 (8.8) kg (range 45.6-79.9). Differences in the mean AUC(0-∞) were 12.7 (4.4) and 14.2 (6.6) ng/mL/h in pomegranate juice and control groups, respectively (geometric mean ratio: 1.02 [95% CI, 0.95-1.09]; P = 0.40). Differences in C(max) for midazolam did not reach the level of statistical significance (5.1 [1.7] vs 5.0 [2.0] ng/mL, geometric mean ratio: 0.95 [95% CI, 0.79-1.11]; P = 0.68). Excretions of 1'-hydroxymidazolam (P = 0.34) and 4-hydroxymidazolam (P = 0.32) were not significantly altered by ingestion of pomegranate juice. CONCLUSION: In this small Japanese adult volunteer population receiving single subtherapeutic doses of midazolam, 2 weeks' consumption of pomegranate juice did not significantly alter the pharmacokinetic profile of midazolam compared with that of the control. Protocol identifier: UMIN000004459.

Inhibition of the terminal differentiation of odontoblasts and their transdifferentiation into osteoblasts in Runx2 transgenic mice.

Runx2 is an essential transcription factor for bone and tooth development whose function in odontoblast differentiation remains to be clarified. To pursue this issue, we examined tooth development in Runx2 transgenic mice under the control of Col1a1 promoter (Tg(Col1a1-Runx2) mice). Endogenous Runx2 protein was detected in the nuclei of preodontoblasts, immature odontoblasts, mesenchymal cells in the dental sac, and osteoblasts, while transgene expression was detected in odontoblasts and osteoblasts. Odontoblasts in Tg(Col1a1-Runx2) mice lost their columnar shape and dentin was deposited around the odontoblasts, which were cuboid or flat in shape. The dentin in Tg(Col1a1-Runx2) mice was thin and possessed lacunae that contained odontoblasts and bone canaliculi-like structures, while predentin and dentinal tubules were absent. We examined the expression of dentin matrix protein genes, Col1a1 and dentin sialophosphoprotein (DSPP), by in situ hybridization, and dentin matrix proteins, osteocalcin, osteopontin, and dentin matrix protein 1 (DMP1) as well as an intermediate filament, nestin, by immunohistochemistry to characterize odontoblasts in Tg(Col1a1-Runx2) mice. Results showed Col1a1 expression was down-regulated, DSPP expression was lost, and nestin expression was severely decreased in the odontoblasts of Tg(Col1a1-Runx2) mice. Further, the expressions of osteocalcin, osteopontin, and DMP1 were up-regulated in odontoblasts, although the up-regulation of osteocalcin expression was transient. These findings indicate that Runx2 inhibits the terminal differentiation of odontoblasts, and that Runx2 induces transdifferentiation of odontoblasts into osteoblasts forming a bone structure. Thus, Runx2 expression has to be down-regulated during odontoblast differentiation to acquire full odontoblast differentiation for dentinogenesis.

Design and optimization of a recombinant system for large-scale production of the MPT64 antigen from Mycobacterium tuberculosis.

Early clinical trials of a potential new tuberculosis (TB) diagnostic, the Patch Test for Active TB (PTAT), used MPB64 protein that was purified from the spent medium of Bacillus Calmette-Guérin (BCG) Tokyo 172 vaccine production. The yield was poor, 0.05 mg/L, and the process for purification of the protein was complex, requiring four chromatographic steps. The combination of yield and purification complexity compromised the ability to produce the PTAT diagnostic in quantities sufficient for larger clinical trials and commercialization. We report here a highly efficient method for the overexpression and purification of recombinant MPT64 from Escherichia coli (rMPT64) based upon a mild insolubility of rMPT64 following induction, and scalable anion-exchange and gel filtration chromatographies. Yields of protein were improved substantially to approximately 250 mg/L, and resulted in a preparation greater than 98% pure. Quantitative release assays were developed and used with MALDI-TOF mass spectrometry to confirm the identity of rMPT64. Using a guinea pig model of active TB, we found that rMPT64 elicited a specific immune response indistinguishable from that of MPB64 purified from BCG Tokyo culture filtrates. These results describe the first efficient and scalable protocol for production of rMPT64, demonstrate its activity in an animal model of active TB, and lay the foundation of ongoing and future use of the PTAT in clinical settings.

Adhesins encoded by the gingipain genes of Porphyromonas gingivalis are responsible for co-aggregation with Prevotella intermedia.

Co-aggregation among bacterial cells caused by the adherence of one bacterial species to another is a potential colonization mechanism. Several putative aggregation factors for co-aggregation between Porphyromonas (Por.) gingivalis and Prevotella (Pre.) intermedia were partially purified from Por. gingivalis vesicles by gel filtration and affinity chromatography. Antisera against the aggregation factors were made. Analysis using these antisera revealed that 18 and 44 kDa proteins might be responsible for Por. gingivalis vesicle-mediated aggregation of Pre. intermedia. Using antiserum against the 18 kDa protein, the DNA region encoding it was cloned from Por. gingivalis genomic DNA. Sequence analysis revealed that the DNA region was located within the rgpA and kgp genes, encoding Arg-gingipain (Rgp) and Lys-gingipain (Kgp), respectively, and it encoded non-catalytic adhesin domain regions, namely a C-terminal portion of HGP15, the entire HGP17 sequence and an N-terminal portion of HGP27. A portion of the DNA sequence was also found in the haemagglutinin A (hagA) gene. A recombinant glutathione S-transferase (GST)-HGP17 fusion protein reacted to antiserum against the 18 kDa protein and Pre. intermedia cells could adhere to GST-HGP17-conjugated Sepharose 4B beads, indicating that the HGP17 domain protein is responsible for Por. gingivalis vesicle-mediated aggregation of Pre. intermedia.

Effect of Porphyromonas gingivalis vesicles on coaggregation of Staphylococcus aureus to oral microorganisms.

Vesicles from the outer membrane of Porphyromonas gingivalis have the ability to aggregate a wide range of Streptococcus spp., Fusobacterium nucleatum, Actinomyces naeslundii, and Actinomyces viscosus. We found that in the presence of P. gingivalis vesicles, Staphylococcus aureus coaggregated with Streptococcus spp., and the mycelium-type Candida albicans, but not the yeast type. Autoaggregation of S. aureus in the presence of P. gingivalis vesicles is inhibited by L-arginine, L-lysine, and L-cysteine. Both the methicillin-sensitive (MSSA) and -resistant (MRSA) strains of S. aureus were able to coaggregate with Streptococcus spp., A. naeslundii, and A. viscosus when they were treated with P. gingivalis vesicles. P. gingivalis vesicle-treated mycelium-type C. albicans coaggregated with S. aureus, but the yeast-type did not. These results indicate that strains of S. aureus, including MRSA, could adhere to oral biofilms in dental plaque on the tooth surface or in the gingival crevice when P. gingivalis is present.

Development of packaging cell lines for generation of adeno-associated virus vectors by lentiviral gene transfer of trans-complementary components.

Adeno-associated virus (AAV) vector system has several useful advantages with regard to in vitro and in vivo gene transfer. However, their usages have been limited by cumbersome and labor-intensive vector production in the traditional method. To overcome limitations in AAV production, in this report, we explored the possibility of generating AAV packaging cell line, 293T R/C.VA.E2A.E4. cells, by using lentivirus-mediated transduction of Rep/Cap gene of AAV-2, VA RNA, E2A, and E4 genes of Ad5 into 293T cells. In packaging cell lines, it is important that supply of the AAV vector can be stably performed for long time. We showed that the 293T R/C.VA.E2A.E4. cells have stably maintained the transduced components after more than 10 passages and yielded high-titer AAV vectors, and the titer of AAV vectors did not decline even if culture of the packaging cells was continued for long time. The Rep/Cap and E4 gene products caused no remarkable cytotoxicity. The 293T R/C.VA.E2A.E4. cells might be able to tolerate the Rep/Cap and E4 gene products, or have less copy numbers of the Rep/Cap and E4 genes than the traditional method. Moreover, we showed that the AAV vectors derived from 293T R/C.VA.E2A.E4. cells infected the primary human CD34+ haematopoietic progenitor cells with high efficiency (50-70%). In the 293T R/C.VA.E2A.E4. cells, the AAV vectors can be generated by the transfection of one AAV vector plasmid, and large-scale AAV production can be easily achieved. It is important that cumbersome, variable, and costly transfection is avoided.

Autolysis of Porphyromonas gingivalis is accompanied by an increase in several periodontal pathogenic factors in the supernatant.

Porphyromonas gingivalis autolyzes in the culture media. To examine in more detail the molecular components of the autolysate, two-dimensional gel electrophoresis was performed. Many protein spots varied both in number and volume. One of these spots included Arg-gingipain (Rgp) as determined by N-terminal amino acid sequencing. Corresponding to the increase in spot volume, Rgp activity also increased during autolysis. The results of this study suggested that Rgp and other proteins in the P. gingivalis autolysate may be involved with the prolongation of periodontal disease, even after the death of P. gingivalis cells.

Induction of osteoclast differentiation by Runx2 through receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin regulation and partial rescue of osteoclastogenesis in Runx2-/- mice by RANKL transgene.

Receptor activator of nuclear factor-kappaB ligand (RANKL), osteoprotegerin (OPG), and macrophage-colony stimulating factor play essential roles in the regulation of osteoclastogenesis. Runx2-deficient (Runx2-/-) mice showed a complete lack of bone formation because of maturational arrest of osteoblasts and disturbed chondrocyte maturation. Further, osteoclasts were absent in these mice, in which OPG and macrophage-colony stimulating factor were normally expressed, but RANKL expression was severely diminished. We investigated the function of Runx2 in osteoclast differentiation. A Runx2-/- calvaria-derived cell line (CA120-4), which expressed OPG strongly but RANKL barely, severely suppressed osteoclast differentiation from normal bone marrow cells in co-cultures. Adenoviral introduction of Runx2 into CA120-4 cells induced RANKL expression, suppressed OPG expression, and restored osteoclast differentiation from normal bone marrow cells, whereas the addition of OPG abolished the osteoclast differentiation induced by Runx2. Addition of soluble RANKL (sRANKL) also restored osteoclast differentiation in co-cultures. Forced expression of sRANKL in Runx2-/- livers increased the number and size of osteoclast-like cells around calcified cartilage, although vascular invasion into the cartilage was superficial because of incomplete osteoclast differentiation. These findings indicate that Runx2 promotes osteoclast differentiation by inducing RANKL and inhibiting OPG. As the introduction of sRANKL was insufficient for osteoclast differentiation in Runx2-/- mice, however, our findings also suggest that additional factor(s) or matrix protein(s), which are induced in terminally differentiated chondrocytes or osteoblasts by Runx2, are required for osteoclastogenesis in early skeletal development.