Dealing with Community Mental Health post the Fukushima disaster: lessons learnt for the COVID-19 pandemic.

Under the COVID-19 pandemic, mitigation of psychological distress is required. At present, the demand for remote intervention for the numerous affected people is increasing, and telephonic support can be useful. Since the Fukushima nuclear disaster in 2011, we have been developing a large-scale telephonic support system and implementing brief interventions for the Fukushima people identified at risk of psychological problems such as depression and post-traumatic stress disorder. In this article, we report the lessons from the Fukushima disaster that can be applied to the COVID-19 pandemic and describe how the telephonic intervention facilitates easier access to psychological help for people with a broad range of psychological distress who are not able to visit treatment or care resources. In our telephonic intervention, we first sent a mental health and lifestyle survey to the people affected by the Fukushima disaster. The counselor team then provided telephonic intervention to high-risk persons as identified on the basis of the survey results. The individuals had expected to receive from the telephonic system help mainly in the form of stress-coping methods, social resource information such as schools, public offices or medical facilities, and lifestyle advice. Since we also experienced that psychological care for telephone counselors was necessary to mitigate the substantial emotional burden, we used the following three approaches: (i) regular supervision of the telephone counseling methods, (ii) seminars for improvement of counseling skills and (iii) individual psychological support. The positive loops between counselors and consulters will help advance a society affected by a disaster.

More complex transcriptional regulation and stress response by MOF.

MOF (males absent on the first) was initially discovered as a dosage compensation factor that regulates the epigenetic acetylation of histone H4 lysine 16. In this issue, Sheikh et al. demonstrate that MOF expression is not required for normal kidney tissue function but is required for maintaining transcriptional regulation under conditions of stress. This work along with results from previous investigators highlights the importance of the cell lineage-chromatin modification interaction in determining transcriptional programs and physiological outcomes under normal and stress conditions.

Elevation of circulating plasma cytokines in cancer patients with high plasma parathyroid hormone-related protein levels.

Parathyroid hormone (PTH) and PTH-related protein/peptide (PTHrP) bind to the same PTH/PTHrP receptor and stimulate osteoblasts to secrete pro-inflammatory cytokines like interleukin (IL)-6. In patients with primary hyperparathyroidism, elevation of plasma levels of tumor necrosis factor (TNF)-alpha and IL-6 was also described. We, therefore, postulated that PTHrP secreted from cancer cells stimulates the secretion of cytokines and causes increases in their blood levels. Blood concentrations of several cytokines (TNF-alpha, IL-1beta, IL-5, IL-6, IL-8, IL-11 and IL-12) in cancer-bearing patients with or without elevation of blood PTHrP were measured by ELISA. The patients with high plasma PTHrP levels (n=29, intact PTHrP: 8.5 +/- 1.4 pmol/l, normal: <1.1) had higher serum type 1 collagen C-telopeptide (ICTP). Twenty of the patients were hypercalcemic. Plasma concentrations of TNF-alpha, IL-6 and IL-8 were significantly increased in patients with high PTHrP, in either the presence or absence of hypercalcemia. The concentrations of TNF-alpha and IL-6 were also significantly correlated with those of PTHrP. Our observations indicate that high plasma levels of PTHrP in cancer-bearing patients contribute not only to the development of hypercalcemia, but also to the development of the syndrome caused by an excess of pro-inflammatory cytokines.

Comparative study of incadronate and elcatonin in patients with malignancy-associated hypercalcaemia.

The clinical usefulness of incadronate was compared with elcatonin in 26 patients with malignancy-associated hypercalcaemia. Data from 21 and 24 patients could be used to assess efficacy and safety, respectively. Eleven patients were given a single 10-mg intravenous infusion of incadronate and 10 received twice-daily intramuscular injections of 40 IU of elcatonin for 7 consecutive days. After treatment, corrected serum calcium levels decreased significantly in both groups. The anti-hypercalcaemic effect of elcatonin was characterized by its rapid onset, with serum calcium levels reduced 1 day after administration. In contrast, the anti-hypercalcaemic effect of incadronate was more sustained but only became apparent a few days after infusion. Evaluation of symptoms revealed significantly greater improvement rates in the incadronate group compared with the elcatonin group. Adverse drug reactions were observed in three patients in the incadronate group, i.e. mild and transient fever in two cases and exacerbation of disturbance of consciousness in one case. These findings suggest that incadronate produces more marked and sustained hypocalcaemic effects than elcatonin, and that co-administration of these two drugs may yield both rapid and sustained control of malignancy-associated hypercalcaemia.

Indomethacin lowers the threshold thermal exposure for hyperthermic radiosensitization and heat-shock inhibition of ionizing radiation-induced activation of NF-kappaB.

PURPOSE: It is well established that salicylate and several other non-steroidal anti-inflammatory agents (NSAID), including indomethacin, can activate the heat-shock response, albeit at high concentrations. This is significant since heat shock significantly alters the cellular cytotoxic response to ionizing radiation (IR). It was previously shown that heat shock, as well as NSAIDs, inhibits IR-induced activation of NF-kappaB and that NF-kappaB protects against IR-induced cytotoxicity. Hence, it is hypothesized that pretreatment with indomethacin before heating will lower the temperature and heating times required to inhibit the activation of NF-kappaB and induce significant hyperthermic radiosensitization. MATERIALS AND METHODS: Experiments were performed in HeLa cell lines and the DNA-binding activity was determined by EMSA. Cellular radiosensitivity was determined by clonogenic assay. RESULTS: HeLa cells pretreated with indomethacin showed a decrease in the temperature-time combination necessary to inhibit IR-induction of NF-kappaB DNA binding. In addition, clonogenic cell survival assays using identical conditions showed an indomethacin dose-dependent enhancement of hyperthermic radiosensitization. Thus, similar concentrations of indomethacin both lowered the threshold thermal exposure to inhibit activation of NF-kappaB DNA-binding and increased the sensitivity of tumour cells to hyperthermic radiosensitization-induced cytotoxicity. In HeLa cells treated with N-alpha-tosylphenylalanyl-chloromethyl ketone (TPCK), a serine protease inhibitor that blocks activation of NF-kappaB, an increase in radiosensitivity was observed. Interestingly, no additional cell killing was observed when heat shock was added to cells treated with TPCK before IR, suggesting a possible common cytotoxic pathway. CONCLUSIONS: The results demonstrate that indomethacin lowers the temperature-time conbination necessary to induce several physiological processes associated with the heat-shock response. Furthermore, NSAID may be potential adjuvants in improving the clinical effectiveness of hyperthermia in radiation therapy.

Dose-finding phase I study of simultaneous weekly infusion with doxorubicin and docetaxel in patients with advanced breast cancer.

BACKGROUND: Combination therapy with doxorubicin (DOX) and docetaxel (DOC), given 3 weeks apart, is one of the standard regimens used for treating metastatic breast cancer, but it frequently generates febrile neutropenia. To find a safer regimen with less myelotoxicity and the appropriate dose intensity, we conducted a phase I study of simultaneous weekly infusion with DOX and DOC. METHODS: Twenty-five patients with advanced breast cancer were treated with an intravenous push-injection of DOX that was immediately followed by a 1-h infusion of DOC. This was repeated every week for at least 6 weeks. The premedication employed was three 4-mg doses of dexamethasone every week. Patients were divided into four groups for which the doses of DOX and DOC were escalated in 5-mg/m2 increments. RESULTS: In the 18 patients who were treated with DOX 15 or 20 mg/m2 and DOC 25 mg/m2, or lower, the regimen was found to be tolerable, without febrile episodes. The regimen with 20 mg/m2 of DOX and 30 mg/m2 of DOC was the maximum tolerated dose. Other indications of grade 3 toxicity included asthenia in 4% of patients, anorexia in 8%, and vomiting in 8%. Of the 25 patients, 14 had a partial response. The overall response rate was 56% (95% confidence interval [CI], 35% to 77%). The recommended dose for further trial was 20 mg/m2 of DOX and 25 mg/m2 of DOC. CONCLUSION: Simultaneous weekly infusion with DOX and DOC was feasible, with modest neutropenia and preserved dose intensity. This regimen may be helpful in the management of patients with advanced breast cancer.

An unusual association of monoclonal gammopathy, paroxysmal nocturnal haemoglobinuria and myelodysplastic syndrome transformed into acute myeloid leukaemia: coexistence of triple clonal disorders.

An unusual association of paroxysmal nocturnal haemoglobinuria (PNH), myelodysplastic syndrome (MDS), acute myeloid leukaemia (AML) and monoclonal gammopathy is reported. A 60-year old male, who had a history of IgA monoclonal gammopathy, presented with haemoglobinuria and colic pain. Flow cytometry showed CD55negative/59dim peripheral red cells, and bone marrow examination disclosed MDS. Eleven months, he developed later AML with disappearance of the PNH clones, although the monoclonal gammopathy persisted. The relationship between PNH and MDS has not fully been assessed, although our findings indicate that these triple clonal disorders, all coexisted in one patient.

Comparison of detectability of visual field abnormality by frequency doubling technology in primary open-angle glaucoma and normal-tension glaucoma.

PURPOSE: To compare the effectiveness of frequency doubling technology (FDT) in detecting abnormalities in primary open-angle glaucoma (POAG) and in normal-tension glaucoma (NTG). METHODS: Twenty-nine POAG patients (29 eyes) and 27 NTG patients (27 eyes) were studied. All subjects underwent testing with program C-20 of FDT with appropriate corrective lenses. RESULTS: No significant differences were observed between the two groups in mean age, mean deviation (MD), and pattern standard deviation (PSD) measured by the Humphrey Field Analyzer (HFA). The correlation between MD values determined by HFA (x) and FDT (y) is represented by y = 0.60x - 2.7 (r = 0.78, P <.01) in the POAG group and y = 0.59x + 0.6 (r = 0.81, P <.001) in the NTG group. Although the average MD measured by FDT was significantly lower in the POAG group than in the NTG group (P <.05), no significant difference was found in average PSD between the two groups. In early glaucoma cases (MD > or = -5 dB by HFA), a larger proportion of cases in the POAG group than in the NTG group had lower significance level of MD determined by FDT than by HFA (P <.02). At many test points on the temporal periphery in the FDT, the mean sensitivity was lower in the POAG group than in the NTG group; whereas no significant differences among HFA test points were observed. CONCLUSIONS: Frequency doubling technology detected visual field abnormalities in POAG cases more sensitively than in NTG cases. This finding indicates that the pathogenesis of My-cell damage is rather different in POAG and NTG.

Indomethacin-induced radiosensitization and inhibition of ionizing radiation-induced NF-kappaB activation in HeLa cells occur via a mechanism involving p38 MAP kinase.

Although ionizing radiation (IR) activates multiple cellular factors that vary depending on dose and tissue specificity, the activation of NF-kappaB appears to be a well-conserved response in tumor cells exposed to IR. Recently, it also has been demonstrated that nonsteroidal anti-inflammatory agents inhibit tumor necrosis factor and interleukin-1-induced NF-kappaB activation and act as radiosensitizing agents. These observations reinforce the growing notion that NF-kappaB may be a protective cellular factor responding to the cytotoxicity of IR and other damaging stimuli. As such, we addressed the idea and mechanism that NF-kappaB is a downstream target of the nonsteroidal anti-inflammatory agent indomethacin and is involved in the process of radiosensitization. In this study, we report that indomethacin inhibited IR-induced activation of NF-kappaB and sensitized HeLa cells to IR-induced cytotoxicity at similar concentrations. Pretreatment of HeLa cells with SB 203580, a pyridinyl imidazole compound that specifically inhibits p38 mitogen-activated protein kinase (MAPK), abrogated the ability of indomethacin to inhibit IR-induced activation of NF-kappaB and diminished the indomethacin radiosensitizing effect. In addition, the transient genetic activation of p38(MAPK) inhibited IR induction of NF-kappaB gene expression in the absence of indomethacin. Finally, permanently transfected cell lines genetically unable to activate NF-kappaB, because of expression of a dominant negative I-kappaBalpha gene, demonstrated increased sensitivity to IR-induced cytotoxicity. Taken together, these results suggest that p38 MAPK is a target involved in indomethacin-induced radiosensitization and that NF-kappaB may be one downstream target in this process.

Another function for the mitochondrial ribosomal RNA: protein folding.

Specialized proteins known as molecular chaperones bind transiently to non-native conformational states of proteins and protein complexes to promote transition to a biologically active conformation. Recently, it was demonstrated in vitro that proteins do not uniquely possess this activity. We show that mitochondrial 12S and 16S ribosomal RNA can fold chemically denatured proteins and reactivate heat-induced aggregated proteins in vitro. This chaperone action is ATP-independent. The specific secondary structure of the mitochondrial rRNA is critical to its folding activity. Furthermore, mutant mitochondrial 16S rRNA from aged cardiac muscle cells lacked this activity. We propose that mitochondrial 12S and 16S ribosomal RNA may play an important role in protein folding in mitochondria.

[Comparison of detectability of visual field abnormality by frequency doubling technology in primary open-angle glaucoma and normal-tension glaucoma].

PURPOSE: To compare the effectiveness of frequency doubling technology(FDT) in detecting abnormalities in primary open-angle glaucoma(POAG) and normal-tension glaucoma(NTG). SUBJECTS AND METHODS: Twenty-nine POAG patients (29 eyes) and 27 NTG-patients(27 eyes) were studied. All subjects underwent testing with program C-20 of FDT with appropriate corrective lenses. RESULTS: No significant differences were observed between the two groups in mean age, mean deviation(MD), and pattern standard deviation(PSD) measured by the Humphrey Field Analyzer(HFA). The correlation between MD values determined by HFA(x) and FDT(y) is represented by y = 0.60x - 2.7 (r = 0.78, p < 0.01) in the POAG group and y = 0.59x + 0.6 (r = 0.81, p < 0.001) in the NTG group. No significant difference was found in the average PSD between the two groups. In early glaucoma cases (MD > or = -5 dB by HFA), a larger proportion of cases in the POAG group than the NTG group had a lower significance level of MD determined by FDT than by HFA (p < 0.02). At many test points on the temporal periphery in FDT the mean sensitivity was lower in the POAG group than in the NTG group; whereas no significant differences among HFA test points were observed. CONCLUSIONS: FDT detected visual field abnormalities in POAG cases more sensitively than in NTG cases. This finding indicates that the pathogenesis of My-cell damage is different in POAG and NTG.

Characterization of homo- and heterodimerization of cardiac Csx/Nkx2.5 homeoprotein.

Csx/Nkx2.5 is an evolutionarily conserved homeodomain (HD)-containing transcription factor that is essential for early cardiac development. We found that the HD of Csx/Nkx2.5 binds as a monomer as well as a dimer to its DNA binding sites in the promoter of the atrial natriuretic factor (ANF) gene, an in vivo target gene of Csx/Nkx2.5. Csx/Nkx2.5 physically interacts with each other in vitro as well as in cells, and the HD is critical for homodimerization. Lys(193) and Arg(194), located at the COOH-terminal end of HD, are essential for dimerization. Lys(193) is also required for a specific interaction with the zinc finger transcription factor GATA4. Csx/Nkx2.5 can heterodimerize with other NK2 homeodomain proteins, Nkx2.3 and Nkx2.6/Tix, with different affinities. A single missense mutation, Ile(183) to Pro in the HD of Csx/Nkx2.5, preserved homodimerization function, but totally abolished DNA binding. Ile(183) --> Pro mutant acts in an inhibitory manner on wild type Csx/Nkx2.5 transcriptional activity through the ANF promoter in 10T1/2 cells. However, Ile(183) --> Pro mutant does not inhibit wild type Csx/Nkx2.5 function on the ANF promoter in cultured neonatal cardiac myocytes, possibly due to failure of dimerization in the presence of the target DNA. These results suggest that complex protein-protein interactions of Csx/Nkx2.5 play a role in its transcriptional regulatory function.

[Oral cancer chemotherapy in the clinic].

The present status of oral chemotherapeutic agents and the treatment of cancer were reviewed. Twenty anticancer agents are commercially available in Japan excluding hormonal and BRM agents. Cancers for the outpatient chemotherapy are limited because useful drugs are few for such circumstances. Now new potent agents such as S-1, capecitabine and molecular targeting are available. This kind of chemotherapy is needed for growing number of elderly patients for QOL and medical cost.

Phase II study of S-1, a novel oral fluorophyrimidine derivative, in patients with metastatic colorectal carcinoma. S-1 Cooperative Colorectal Carcinoma Study Group.

This study set out to evaluate, in patients with metastatic colorectal carcinoma, the efficacy and toxicity of S-1, which contains tegafur, 5-chloro-2,4-dihydroxypyridine (CDHP) and potassium oxonate, based on a biochemical modulation of 5-fluorouracil (5-FU) targeted at inhibition of dihydropyrimidine dehydrogenase (DPD). Sixty-three patients with measurable metastatic colorectal carcinoma were enrolled into the study. None of the patients had received prior chemotherapy except for adjuvant setting. S-1 was administered orally twice daily at a standard dose of 80 mg m(-2) day(-1) for 28 days followed by a 14-day rest. This agent is continued until disease progression, unaccepted toxicity, or patient refusal. Twenty-two (35%) of the 62 eligible patients achieved PR with a 95% confidence interval of 25-48%. Five of the 10 patients with a history of adjuvant chemotherapy achieved partial remission. The median survival time was 12 months. Major adverse reactions included myelosuppressive and gastrointestinal toxicities, though their incidence of grade 3 or 4 being 13% in neutropenia and less than 10% in the others. None of the 53 patients treated as outpatients required hospitalization due to adverse reactions: These results suggest that S-1 achieves similar responses to those of infusional 5-FU plus leucovorin and shows the potential of another biochemical modulation with easily manageable toxicity.

An early phase II study of oral S-1, a newly developed 5-fluorouracil derivative for advanced and recurrent gastrointestinal cancers. The S-1 Gastrointestinal Cancer Study Group.

5-Fluorouracil (5-FU) or a 5-FU derivative 1-(2-tetrahydrofuryl)-5-fluorouracil (FT) has been widely prescribed for patients with gastrointestinal cancer. However, the phosphorylation of 5-FU in the digestive tract causes gastrointestinal toxicities. 5-FU is also rapidly degraded to alpha-fluoro-beta-alanine after contact with dihydropyrimidine dehydrogenase (DPDase) which is mainly present in the liver. Therefore, to overcome these metabolic events, S-1, an antitumor agent was developed, based on the biochemical modulation of FT by 5-chloro-2,4-dihydroxypyridine (CDHP) and potassium oxonate (Oxo), in a molar ratio of 1:0.4:1. The antineoplastic effect of S-1, was examined in Japanese patients with advanced gastric (G) or colorectal (C) cancer in a multicenter early phase II study involving 24 centers throughout Japan. The patients were prescribed a minimum of 2 courses of S-1 orally, with each course consisting of 75 or 50 mg (in terms of FT) twice a day for 28 days followed by withdrawal for 2 weeks. Thirty-one patients with G and 31 C were entered into this study. The clinical response and extent of toxicity were evaluated in G 28 and C 30 cases, respectively. Nine (32.1%) G patients and 14 (46.7%) C patients had been treated previously with other anticancer drugs. In G patients, there was a 53.6% (15/28) and in C patients a 16.7% (5/30) response rate (90% confidence interval G 38.4-68.1% and C 8.4-30.5%) with 15 (53.6%) (G) and 5 (16.7%) (C) partial responses (PR), and these responses persisted for 79 days (G) and 120 days (C) (median value). In particular, the response rate for the primary lesion was 27.8% (5/18) (G) and 33.3% (1/3) (C). No change (NC) in the disease was observed in 4 (14.3%) (G) and 13 (43.3%) (C) patients, and in 6 (21. 4%) (G) and 7 (23.3%) (C) the disease progressed (PD). At the time of analysis, the median survival was 298 days (G) and 358 days (C). Major adverse effects consisted of gastrointestinal symptoms and myelosuppression while toxicities of grade 3 or more occurred in 35. 7% (10/28) (G) and 33.3% (10/30) (C). Based on these data, S-1 is considered to have positive effects in patients with advanced gastrointestinal cancer.

Phase II study of raltitrexed (Tomudex) in chemotherapy-pretreated patients with advanced colorectal cancer. Tomudex Cooperative Study Group.

Raltitrexed (Tomudex), a novel folate-based inhibitor of thymidylate synthase, has demonstrated anti-tumour efficacy comparable with 5-fluorouracil and leucovorin in patients with advanced colorectal cancer (CRC). This phase II study was conducted to evaluate the anti-timor efficacy and tolerability of raltitrexed in patients with advanced CRC who had received one previous chemotherapy regimen. Raltitrexed was administered at a dose of 3.0 mg/m2 i.v. over 15 min once every 3 weeks. Of 43 eligible patients, 53% had colon cancer and 47% rectal cancer. Objective responses were observed in 16% of patients [95% confidence interval (CI): 7-31%; seven partial responses). The median duration of response was 101 days (range: 45-239 days), the median overall duration of response was 145 days (range: 104-302 days) and the median survival was 11.6 months (95% CI: 9.4-14.7 months). Liver metastases showed a 17% (three of 18) response rate and lung metastases a 12% (three of 25) response rate. Adverse events of grade 3 or 4 reported for more than 5% of patients were neutropenia (23%), leukopenia (9%), reversible SGPT increase (7%) nausea/vomiting (19%), anorexia (14%), asthenia (9%) and hypotension (7%). Grade 3 or 4 diarrhea, stomatitis and alopecia were not observed. In summary, raltitrexed had an acceptable toxicity profile and promising anti-tumor activity against advanced CRC in patients who had received prior chemotherapy. Further clinical trials of combination chemotherapy using raltitrexed are warranted.

Pharmacokinetic study of S-1, a novel oral fluorouracil antitumor drug.

S-1 is a novel oral fluorouracil antitumor drug that combines three pharmacological agents: tegafur (FT), which is a prodrug of 5-fluorouracil (5-FU); 5-chloro-2,4-dihydroxypyridine (CDHP), which inhibits dihydropyrimidine dehydrogenase (DPD) activity; and potassium oxonate (Oxo), which reduces gastrointestinal toxicity. Phase I and early Phase II clinical trials have already been completed. On the basis of the results of these trials, 80 mg/m2/day, given daily in two divided doses after breakfast and supper, a 28-day consecutive oral regimen is recommended. In this study, we investigated the pharmacokinetics of 5-FU, intact FT, CDHP, and Oxo, after administration of S-1, at a standard dose of 80 mg/m2/day, in advanced cancer patients. Twelve patients were recruited to the study; 5 patients with gastric cancer, 4 with colorectal cancer, and 3 with breast cancer. Among them, analysis was conducted on 12 patients for single administration and on 10 patients for consecutive administration. The initial dose of S-1 for each patient was determined according to his/her body surface area (BSA) as follows: for BSA < 1.25 m2, 80 mg/body/day; for 1.25 m2 < or = BSA < 1.5 m2, 100 mg/day; and for 1.5 m2 < or = BSA, 120 mg/day. For single administration, half of the standard dose was used. For 28-day consecutive administration, the standard dose was given daily in two divided doses. The average single dose per BSA was 35.9 mg/m2 (31.7-39.7 mg/m2). Pharmacokinetic parameters of plasma 5-FU were as follows: Cmax, 128.5 +/- 41.5 ng/ml; Tmax, 3.5 +/- 1.7 h; AUC(0-14), 723.9 +/- 272.7 ng x h/ml; and T(1/2), 1.9 +/- 0.4 h. In the 28-day consecutive regimen, there were no fluctuations in pharmacokinetics nor any drug accumulation. Because the pharmacokinetics of orally administered S-1 is almost similar to that of continuous i.v. infusion of 5-FU, we concluded that S-1 may improve patients' quality of life.

[Multi-drug resistant breast cancer responding to chemotherapy with docetaxel (taxotere: TXT)].

The patient was a fifty-five year old female who had stage IVb advanced breast cancer with hypoxia due to bilateral pulmonary metastases and lymphangitis. The cancer was adriamycin (ADM) and multi-drug resistant. We administered docetaxel (taxotere: TXT) 60 mg/m2 every 3 weeks. After 2 courses, the pulmonary metastases had become remarkably reduced in size and hypoxia was reduced and performance status (PS) improved. Major toxic defects were grade-4 neutropenia and hair loss. The patient could be discharged from the hospital without O2 inhalation and enjoyed a better quality of life (QOL). This chemotherapy is thought to be effective against ADM and multi-drug resistant breast cancer.

Isolation of differentially expressed cDNAs from p53-dependent apoptotic cells: activation of the human homologue of the Drosophila peroxidasin gene.

Inactivation of the p53 tumor suppressor protein has been observed in a large number of human cancers. Overexpression of p53 induces either growth arrest or programmed cell death (apoptosis). The growth arrest function of p53 is mediated by induction of p21 (WAF1/CIP1), but the mechanisms underlying p53-dependent apoptosis are still largely unknown. To investigate these mechanisms, we have identified six differentially expressed transcripts in a human colon cancer cell line undergoing p53-dependent apoptosis. One of the p53-responsive genes showed significant homology to Drosophila peroxidasin, an extracellular matrix-associated peroxidase, and is likely to be its human homologue. Our results suggest a possible connection between p53-dependent apoptosis and the production of reactive oxygen species.