Systemically Administered RNAi Molecule Sensitizes Malignant Pleural Mesotheliomal Cells to Pemetrexed Therapy.

Pemetrexed (PMX) is a key drug for the management of malignant pleural mesothelioma (MPM). However, its therapeutic efficacy is cruelly restricted in many clinical settings by the overexpression of thymidylate synthase (TS) gene. Recently, we emphasized the efficacy of locally administered shRNA designed against TS gene in enhancing the cytotoxic effect of PMX against orthotopically implanted MPM cells in tumor xenograft tumor model. Herein, we explored the efficiency of systemic, rather than local, delivery of TS RNAi molecule in sensitizing MPM cells to the cytotoxic effect of PMX. We here designed a PEG-coated TS shRNA-lipoplex (PEG-coated TS shRNA-lipoplex) for systemic injection. PEG modification efficiently delivered TS shRNA in the lipoplex to tumor tissue following intravenous administration as indicated by a significant suppression of TS expression level in tumor tissue. In addition, the combined treatment of PMX with systemic injection of PEG-coated TS shRNA-lipoplex exerted a potent antitumor activity in a s.c. xenograft tumor model, compared to a single treatment with either PMX or PEG-coated TS shRNA-lipoplex. Metastasis, or the spread, of mesothelioma substantially dedicates the effectiveness of treatment options. The systemic, in addition to local, delivery of tumor targeted anti-TS RNAi system we propose in this study might be an effective option to extend the clinical utility of PMX in treating malignant mesothelioma.

Exploring the Potential Use of Natural Products Together with Alkalization in Cancer Therapy.

Cancer treatment is a significant focus in medicine, owing to the increasing global incidence of cancers. Patients with advanced cancers that do not respond to conventional therapies have limited options and an unfavorable prognosis. Consequently, researchers are investigating complementary approaches to conventional treatments. One such approach is alkalization therapy, which aims to neutralize the acidic tumor microenvironment (TME) by increasing its pH level. The acidic TME promotes inflammation, tumor progression, and drug resistance. Alkalization therapy has been demonstrated to be effective for various cancers. In addition, natural products, such as triterpenoids, parthenolides, fulvic acid, Taxus yunnanensis, and apple pectin have the potential to alleviate symptoms, maintain physical fitness, and improve treatment outcomes of cancer patients through their anti-inflammatory, antioxidant, and anticancer properties. In this review, we focus on the effects of alkalization therapy and natural products on cancer. Furthermore, we present a case series of advanced cancer patients who received alkalization therapy and natural products alongside standard treatments, resulting in long-term survival. We posit that alkalization therapy together with supplementation with natural products may confer benefits to cancer patients, by mitigating the side effects of chemotherapy and complementing standard treatments. However, further research is warranted to validate these clinical findings.

Effects of alkalization therapy on hepatocellular carcinoma: a retrospective study.

Background: In hepatocellular carcinoma (HCC) patients, is difficult to prevent recurrence even when remission is achieved. In addition, even with the advent of drugs that are effective for the treatment of HCC, a satisfactory extension of patient survival has not been achieved. To overcome this situation, we hypothesized that the combination of alkalization therapy with standard treatments will improve the prognosis of HCC. We here report the clinical results of HCC patients treated with alkalization therapy at our clinic. Patients and methods: Patients with HCC treated at Karasuma Wada Clinic (in Kyoto, Japan), from January 1, 2013, to December 31, 2020 were analyzed. Overall survival (OS) from both the time of diagnosis and the start of alkalization therapy for each patient was compared. The mean urine pH was also calculated as a surrogate marker of tumor microenvironment pH, and OS from the start of alkalization therapy was compared between patients with a mean urine pH of ≥ 7.0 and those with a mean urine pH of < 7.0. Results: Twenty-three men and six women were included in the analysis, with a mean age at diagnosis of 64.1 years (range: 37-87 years). Seven of the 29 patients had extrahepatic metastases. Patients were divided into two groups according to their mean urine pH after the initiation of alkalization therapy: 12 of the 29 patients had a mean urine pH of ≥ 7.0, and 17 had a mean urine pH of < 7.0. The median OS from diagnosis was 95.6 months (95% confidence interval [CI] = 24.7-not reached), and from the start of alkalization therapy was 42.3 months (95% CI = 8.93-not reached). The median OS from the start of alkalization therapy in patients with a urine pH of ≥ 7.0 was not reached (n = 12, 95% CI = 3.0-not reached), which was significantly longer than that in patients with a pH of < 7.0 (15.4 months, n = 17, 95% CI = 5.8-not reached, p < 0.05). Conclusions: The addition of alkalization therapy to standard therapies may be associated with more favorable outcomes in HCC patients with increased urine pH after alkalization therapy.

Corrigendum: Effects of alkalization therapy on hepatocellular carcinoma: a retrospective study.

[This corrects the article DOI: 10.3389/fonc.2023.1179049.].

Potential of Alkalization Therapy for the Management of Metastatic Pancreatic Cancer: A Retrospective Study.

Current treatments for patients with pancreatic cancer offer limited benefits. In this study, we applied alkalization therapy, which was efficacious for other solid tumors at our clinic, to stage 4 pancreatic cancer patients, and investigated its effect on disease prognosis. Patients with metastatic pancreatic cancer who were treated at Karasuma Wada Clinic in Kyoto, Japan, between January 2011 and April 2022, were included in the study. All patients received alkalization therapy (a combination of an alkaline diet, bicarbonate, and citric acid administration), alongside standard chemotherapy. Urine samples were collected to assess urine pH as a marker of whole-body alkalization. In the 98 patients analyzed, the median overall survival (OS) from the time of diagnosis was 13.2 months. Patients with a mean urine pH of 7.5 or greater had a median OS of 29.9 months, compared with 15.2 months for those with a mean urine pH of 6.5 to 7.5, and 8.0 months for those with a mean urine pH of less than 6.5, which suggests a trend of a longer OS in patients with a higher urine pH (p = 0.0639). Alkalization therapy may offer a viable approach to extending the survival of stage 4 pancreatic cancer patients, who typically have an unfavorable prognosis.

[Developmental effects of perinatal hypothyroidism on cognitive functions: focused on attention].

PURPOSE: Thyroid hormones are essential for the development of brain. Perinatal hypothyroidism induced by environmental endocrine disrupters is reported to cause cognitive dysfunctions such as attention and memory deficits. The purpose of this study is whether perinatal hypothyroidism causes deficits of shift attention and divided attention in offspring using a target detection task. METHODS: Pregnant rats were treated with the anti-thyroid drug methimazole [0.02% (w/v)] from gestational day 15 to postnatal day 21. The offspring received behavioral testing using shift attention and divided attention tasks. The testing of shift attention started with the presentation of one of two targets. A lever was inserted to the same side as the presented target (ipsilateral trial). However, a lever was inserted to the opposite side to the presented target with the probability of 20% (contralateral trial). Next, the testing of divided attention was introduced. The testing started with the presentation of one of the two targets (one-side trial). A lever was inserted to the same side as the presented target. However, both targets were presented (both-side trial) and one of the two levers was inserted with the probability of 20%. RESULTS AND DISCUSSION: On the contralateral trials in the shift attention task, the untreated rats responded frequently with reaction times of 1.4-1.6 s, whereas the treated rats responded sporadically with a wide range of reaction times of 1.2-7.2 s. This indicates that the treated rats were not able to shift their attention quickly toward the opposite side. When the both-side targets were presented in the divided attention task, the untreated rats responded frequently with the reaction times of 0.6-0.8 s and 1.4-1.6 s. The treated rats responded frequently with reaction times of 0.8-1.0 s and 1.0-6.4 s. Both the untreated and treated rats did not divide their attention toward the both-side targets but probably paid attention to one of the two targets. They responded with the shorter reaction times when the lever was inserted in the same side that they paid attention and responded with longer reaction times when the lever was inserted in the opposite side. We conclude that perinatal hypothyroidism affects shift attention in rats but further researches are necessary to examine whether hypothyroidism affects divided attention. CONCLUSION: Perinatal hypothyroidism causes the deficit of shift attention in rats but it was unclear whether hypothyroidism affects divided attention.

Meaning and Significance of "Alkalization Therapy for Cancer".

Objectives of the Study: Our research aims to answer the following questions. Can cancer progression be stopped by changing the body condition of person with cancer? Can cancer be cured?If cancer progression can be stopped, what is the underlying mechanism? Theoretical Rationale for Alkalization Therapy: Almost 70 years ago, Goldblatt H. & Cameron G. reported on the idea of alkalization therapy. Before that, Otto Warburg had been studying the metabolism of cancer and had discovered the essential nature of cancer. He published a review in Science in 1956 under the title "On the origin of cancer cells". From his phenomena described above, we established the theoretical rationale for alkalization therapy, based on the question of "How does cancer form and what is its nature"? Limitations of Deductive Methods and Inductive Approaches: In this paper, we describe a method to reconstruct the limitations and weaknesses of modern cancer medicine as Science-based Medicine using an inductive method, and to present a new vision of cancer therapy. How should we treat cancer? (Case presentation): Using a specific clinical case, we present patients in whom were successfully treated with no or few anticancer drugs. Summary: The biggest weakness of current cancer treatments is that they only treat the cancer and not the actual patient. The "alkalization therapy" that we advocate does not compete with any of the current standard treatments, but improves the effectiveness of standard treatments, reduces side effects, and lowers medical costs.

Clinical review of alkalization therapy in cancer treatment.

One of the most unique characteristics of cancer metabolism is activated aerobic glycolysis, which is called the "Warburg effect", and is a hallmark of cancer. An acidic tumor microenvironment (TME) resulting from activated anaerobic glycolysis is associated with cancer progression, multi-drug resistance, and immune escape. Several in vitro and in vivo studies reported that neutralization of the acidic TME by alkalizing agents, such as bicarbonate, resulted in the suppression of cancer progression and a potential benefit for anti-cancer drug responses. In clinical settings, alkalizing effects were achieved not only by alkalizing agents, but also by a following a particular diet. An epidemiological study demonstrated that more fruits and vegetables and less meat and dairy products are associated with an increase in urine pH, which may reflect the alkalizing effect on the body. However, it remains unclear whether alkaline dietary intervention improves the effects of cancer treatment. Moreover, there are few clinical reports to date regarding cancer treatments being performed on patients together with alkalization therapy. In this review, we investigated whether alkalization therapy, which includes an alkaline diet and/or alkalizing agents, improves cancer treatment.

Cellular analysis of SOD1 protein-aggregation propensity and toxicity: a case of ALS with slow progression harboring homozygous SOD1-D92G mutation.

Mutations within Superoxide dismutase 1 (SOD1) cause amyotrophic lateral sclerosis (ALS), accounting for approximately 20% of familial cases. The pathological feature is a loss of motor neurons with enhanced formation of intracellular misfolded SOD1. Homozygous SOD1-D90A in familial ALS has been reported to show slow disease progression. Here, we reported a rare case of a slowly progressive ALS patient harboring a novel SOD1 homozygous mutation D92G (homD92G). The neuronal cell line overexpressing SOD1-D92G showed a lower ratio of the insoluble/soluble fraction of SOD1 with fine aggregates of the misfolded SOD1 and lower cellular toxicity than those overexpressing SOD1-G93A, a mutation that generally causes rapid disease progression. Next, we analyzed spinal motor neurons derived from induced pluripotent stem cells (iPSC) of a healthy control subject and ALS patients carrying SOD1-homD92G or heterozygous SOD1-L144FVX mutation. Lower levels of misfolded SOD1 and cell loss were observed in the motor neurons differentiated from patient-derived iPSCs carrying SOD1-homD92G than in those carrying SOD1-L144FVX. Taken together, SOD1-homD92G has a lower propensity to aggregate and induce cellular toxicity than SOD1-G93A or SOD1-L144FVX, and these cellular phenotypes could be associated with the clinical course of slowly progressive ALS.

γδ T-cell immunotherapy for lung cancer.

Lung cancer is the leading cause of cancer death worldwide, yet there are still no satisfactory protocols available for treating this disease, emphasizing the urgency for more effective therapies. Recent clinical trials have provided encouraging evidence of the benefits of certain forms of immunotherapy. Here, we summarize recent developments in the area of γδ T-cell therapy for lung cancer in our center. γδ T cells constitute 2%-10% of T lymphocytes in human blood and play a role in immune surveillance against microbial pathogens and, possibly, cancer. These T cells recognize phosphoantigens via polymorphic γδ T-cell antigen receptors (TCR), as well as the major histocompatibility complex (MHC) class I chain-related molecules, A and B (MICA and MICB), via nonpolymorphic NKG2D receptors in an MHC-unrestricted manner. This implies that γδ T cells could retain antitumor effects despite reduced expression of MHC and tumor antigens on cancer cells. Thus, clinical trials have been conducted to evaluate the safety and efficacy of γδ T-cell-based immunotherapies for non-Hodgkin lymphoma, multiple myeloma, and solid tumors. This review focuses on the current status of γδ T-cell-based immunotherapy for lung cancer.

Effects of Ethanol Exposure during Lactation on Ultrasonic Vocalizations of Rat Pups upon Their Isolation: Increase in Pup Distress Calls.

Recording ultrasonic vocalizations (USVs) is a highly sensitive tool to study the dam-pup social relationships, and USV recordings have been used to study the effects of ethanol on pups. Gestational effects of ethanol on the emission of USVs in rat pups have been studied in our previous research. In the present study, the effects of ethanol given to dams during lactation on the acoustic parameters of USVs emitted by isolated pups were examined. Ethanol was administered to dams from postnatal days (PNDs) 5-21. From PNDs 11-21, the high- and low-ethanol-treated dams were exposed to ethanol-containing water (v/v) at concentrations of 30% and 15%, respectively. Tap water without ethanol (0%) was provided to the control dams. The pups in all three ethanol-treated groups were separated from the dam and littermates on PNDs 4, 8, 12, and 16, and USVs produced by the pups were recorded for 5 min. It was found that elevated distress USVs with longer duration and higher percentage of frequency modulations were displayed by the pups from the high-ethanol dams. Alterations in USVs were particularly evident in the pups with a reduced body weight at PND 12. This effect might be because high-ethanol dams showed significantly lower intake of higher ethanol-containing water, and consequently, produced lower amount of milk, as well as exhibited poor maternal care. Insufficient maternal care and malnutrition resulted in pup growth retardation and increased mortality rate in the high-ethanol group, which were not observed in the low-ethanol or control pups. Accordingly, the pups in the high-ethanol group experienced elevated negative emotionality during isolation from their dam and increased emission of USVs. Longer duration and increased frequency modulation of pup USVs are expected to be noticed by the dam and to initiate/increase proper maternal care. It is concluded that ethanol given to lactating mothers has more serious consequences on pup development than the gestational ethanol exposure, and has more harmful effects on pups.

Improved Chemotherapy Outcomes of Patients With Small-cell Lung Cancer Treated With Combined Alkalization Therapy and Intravenous Vitamin C.

Background/Aim: This study aimed to investigate the effects of the combination of alkalization therapy (an alkaline diet and bicarbonate therapy) and intravenous vitamin C treatment on chemotherapy outcomes in patients with small-cell lung cancer (SCLC) (study registration: UMIN000043056). Patients and Methods: Twelve patients with SCLC in the intervention group (receiving both alkalization therapy and vitamin C treatment together with chemotherapy) were retrospectively compared to 15 patients with SCLC in the control group (receiving chemotherapy only). Results: The mean urine pH of the intervention group was significantly higher than that of the control group (7.32±0.45 vs. 6.44±0.74, respectively; p<0.005). The median overall survival for the intervention group was 44.2 months (95% confidence interval=22.0-not reached), as compared with 17.7 months for the control group (95% confidence intervaI=13.5-not reached; p<0.05). Conclusion: The combination of alkalization therapy and intravenous vitamin C treatment may be associated with favorable outcomes in patients with SCLC receiving chemotherapy.

Effect of foot-floor friction on the external moment about the body center of mass during shuffling gait: a pilot study.

Herein, we investigated the effect of friction between foot sole and floor on the external forward moment about the body center of mass (COM) in normal and shuffling gaits. Five young male adults walked with normal and shuffling gaits, under low- and high-friction surface conditions. The maximum external forward moment about the COM (MEFM-COM) in a normal gait appeared approximately at initial foot contact and was unaffected by floor condition. However, MEFM-COM in a shuffling gait under high-friction conditions exceeded that under low-friction conditions (p < 0.001). Therein, MEFM-COM increased with an increasing utilized coefficient of friction at initial foot contact; this effect was weaker during a normal gait. These findings indicate that increased friction between foot sole and floor might increase tripping risk during a shuffling gait, even in the absence of discrete physical obstacles.

Mutations in Keap1 are a potential prognostic factor in resected non-small cell lung cancer.

BACKGROUND: Mutations in Kelch-like ECH-associated protein 1 (Keap1) have been reported to protect tumor cells from chemotherapeutic agents. However, their prognostic significance in nonsmall cell lung cancer (NSCLC) is still unclear. In this study, we examined the effect of Keap1 gene mutations on survival and disease-free interval using resected primary NSCLC tissue. METHODS: We retrospectively analyzed the tumors from 79 patients with completely resected pathological Stage I-II NSCLC for the presence of Keap1 gene mutations and examined the prognosis of the patients. RESULTS: Keap1 gene mutations were detected in four patients (5.1%). The postoperative 5-year survival rate for patients with Keap1 mutations was significantly lower than those without a mutation (25% vs. 76%, P = 0.038). The postoperative 5-year disease-free survival rate for patients with a mutant Keap1 tumor was slightly lower than for patients with Keap1 wild-type tumors (25% vs. 66%, P = 0.057). CONCLUSIONS: Keap1 gene mutations are likely to be associated with a worse prognosis and lower postoperative disease-free survival rates in pathological Stage I-II NSCLC.

Thrombin induces rapid disassembly of claudin-5 from the tight junction of endothelial cells.

The cell-to-cell junction of endothelial cells (ECs) regulates the fence function of the vascular system. Previously we showed that ECs derived from embryonic stem cells (i.e., EECs) develop to form stable endothelial sheets in monolayer cultures. Immunohistochemical analysis revealed that these EECs formed intercellular junctions with the help of vascular endothelial cadherin (VECD) and claudin-5. In this study, we investigated the response of EC sheets to stimuli that are known to increase vascular permeability. While vascular endothelial growth factor A and histamine disrupted the EC junction by enhancing contraction of EECs, thrombin affected specifically the localization of claudin-5 at this junction. We could not detect any significant effect of thrombin on the localization of VECD. Concerning thrombin receptors, EECs expressed protease-activated receptor 1 (PAR1) but not PAR4. Consistent with this expression pattern, PAR1 agonists eliminated claudin-5 as effectively as thrombin itself. This is the first report to show that claudin-5 can be disassembled from the EC junction in a signal-dependent manner and to suggest that claudin-5 mobilization is a cause of PAR1-induced increase in vascular permeability.

Forced oscillation technique as a non-invasive assessment for lung transplant recipients.

We usually use spirometry for the medical follow-up of respiratory mechanics after lung transplantation. However, especially in the first few post-operative weeks, it is easily affected by postoperative pain and the patient's co-operation during forced breathing effort. To avoid missing out on assessing pulmonary function, we perform non-invasive forced oscillation techniques on the patients who cannot perform forced breathing maneuvers. In this paper, we discuss the application of forced oscillation techniques on a patient with suspicion of acute lung rejection, whose spirometry could not be correctly performed and seemed to be unreliable. The respiratory impedance measurements had good correlation with the patient's clinical symptoms before and after steroid therapy. Thus, postoperative pulmonary function follow-up using forced oscillation technique was useful in assessing peripheral airway condition in critically ill patients, and may be able to detect acute rejection.

Effects of prenatal ethanol exposure on acoustic characteristics of play fighting-induced ultrasonic vocalizations in juvenile rats.

Juvenile rats display rough-and-tumble playing with conspecifics (play fighting behavior) and produce 22 and 50 kHz ultrasonic vocalizations (USVs). The 22 kHz USV is considered to reflect negative emotionality such as anxiety, fear, and distress, whereas the 50 kHz USV is considered to reflect positive emotionality such as joy, happiness, and satisfaction. USV is a sensitive tool for measuring emotionality in socially interactive situations. However, effects of prenatal ethanol-exposure on the acoustic characteristics of play fighting-induced USVs have remained unclear. In Experiment I, we recorded USVs produced by prenatally ethanol-exposed rats during play fighting on postnatal days (PNDs) 40-42 and examined the acoustic characteristics of negative and positive emotion-induced USVs. In Experiment II, we examined the anxiety levels through elevated plus maze testing on PNDs 37-39 and frequencies of playful attacks on PNDs 43-45 in ethanol-exposed rats. Ethanol was administered to pregnant rats in three gradually increased concentrations between gestational days (GDs) 8 and 20. From GDs 14 to 20, ethanol-containing tap water at concentrations of 30% and 15% (v/v) was administered to the high- and low-ethanol groups, respectively. Tap water without added ethanol was given to the control group. On PNDs 40-42, three rats from the same sex and same ethanol concentration group but from different litters were placed together into a playing cage for play fighting. The high-ethanol male triads displayed elevations of 20-35 kHz USVs reflecting negative emotionality and reductions of 45-70 kHz USVs reflecting positive emotionality compared with both the low-ethanol and control male triads. The high-ethanol male triads had prominent elevations of 20-35 kHz USVs with durations longer than 200 ms, whereas the control male triads did not produce such 20-35 kHz USVs at all. There was no difference in USV acoustic characteristics among the female triads. In addition, the high-ethanol male rats exhibited greater anxiety levels and less frequencies of play fighting than the control male rats. Altogether, we conclude that prenatal exposure to ethanol enhances negative emotionality such as anxiety and, accordingly, 20-35 kHz USVs reflecting negative emotionality are produced with a marked decrease in play fighting, suggesting difficulties in social interactions with conspecifics.

Effects of Alkalization Therapy on Chemotherapy Outcomes in Metastatic or Recurrent Pancreatic Cancer.

BACKGROUND/AIM: The acidic tumor microenvironment is associated both with the progression and drug resistance of cancer. We aimed to investigate the effects of alkalization therapy performed concurrently with chemotherapy on the survival of advanced pancreatic cancer patients (study registration: UMIN 000035659). PATIENTS AND METHODS: Twenty-eight patients with metastatic or recurrent pancreatic cancer were assessed in this study. Alkalization therapy consisted of an alkaline diet with supplementary oral sodium bicarbonate (3.0-5.0 g/day). RESULTS: The mean urine pH was significantly higher after the alkalization therapy (6.85±0.74 vs. 6.39±0.92; p<0.05). The median overall survival from the start of alkalization therapy of the patients with high urine pH (>7.0) was significantly longer than those with low urine pH (≤ 7.0) (16.1 vs. 4.7 months; p<0.05). CONCLUSION: An alkalization therapy may be associated with better outcomes in advanced pancreatic cancer patients treated with chemotherapy.

Effects of Alkalization Therapy on Chemotherapy Outcomes in Advanced Pancreatic Cancer: A Retrospective Case-Control Study.

BACKGROUND/AIM: Neutralization of the acidic tumor microenvironment, which is associated with both progression and drug resistance of cancer cells, may be a new treatment option for progressing forms of cancer. We conducted a case-control study to investigate the effects of alkalization therapy, consisting of an alkaline diet with supplementary oral sodium bicarbonate, in patients with metastatic or recurrent pancreatic cancer (study registration no.: UMIN000036126). PATIENTS AND METHODS: Thirty-six patients in the alkalization group (Karasuma Wada Clinic; alkalization therapy plus chemotherapy) were retrospectively compared to 89 patients in the control group (Kyoto University Hospital; chemotherapy only). RESULTS: The median overall survival (OS) in the alkalization group was significantly longer than that in the control group (15.4 vs. 10.8 months; p<0.005). In the alkalization group, mean urine pH was significantly increased after alkalization therapy [6.38±0.85 (before) vs. 6.80±0.71 (after); p<0.05]. Furthermore, the median OS of patients with increased urine pH (pH>7.0 or ΔpH>1.0) in the alkalization group was significantly longer than that of the control group. CONCLUSION: Alkalization therapy may enhance the effects of chemotherapy in patients with advanced pancreatic cancer.

D2-40-positive lymphatic vessel density is a poor prognostic factor in squamous cell carcinoma of the lung.

BACKGROUND: Experimental studies have revealed that D2-40 is useful in identifying the presence of lymphatic invasion in various malignant neoplasms, but the clinical significance remains unclear. The purpose of this study is to assess the clinical significance of D2-40 status in completely resected non-small cell lung cancer. METHODS: A total of 215 consecutive patients with resected pathological stage I-IIIA non-small cell lung cancer were reviewed. Expression of D2-40 in tumor cells and in endothelial cells was examined immunohistochemically, and D2-40-positive lymphatic vessel density (LVD) at the tumor periphery were quantitatively evaluated. RESULTS: D2-40 expression on tumor cells was positive in 55 (25.6%) of 215 patients, and the incidence was significantly higher in squamous cell carcinoma (SCC) patients than in adenocarcinoma patients (48.8% vs. 8.6%, P < .001). D2-40 was also seen on lymphatic vessels in tumor tissues, and the mean number of D2-40-LVD was significantly decreased along with differentiation of tumor cells (P = .038). For all histologic types of tumors, there was no difference in the postoperative survival between higher D2-40-LVD patients and lower D2-40-LVD patients. For SCC, however, lower D2-40-LVD patients showed a significantly better survival than higher D2-40-LVD patients (5-year survival rates, 52.9% vs. 78.9%, P = .040), which was confirmed by a multivariate analyses (P = .048). CONCLUSIONS: D2-40 expression on tumor cells was more frequently seen in SCC than in adenocarcinoma of the lung. In addition, D2-40 expression on lymphatic vessels in tumor tissues was a statistically significant prognostic factor in SCC.