Table 1.
Human studies investigating the role of microbiomes in pancreatic cancer
| Study design | Patients or Samples | Content | Conclusion | Refs |
|---|---|---|---|---|
| Case-control study | ·HOMIM: 10 PC & 10 controls | ·16 of 410 bacterial taxa | Significant changes observed in the microbial composition between pancreatic cancer patients and healthy controls. | [11] |
| ·qPCR: 28 PC & 27 chronic pancreatitis patients & 28 controls | ·Neisseria elongata and Streptococcus mitis | |||
| Meta-analysis | 8 studies of periodontitis or edentulism | RR for periodontitis and PC was 1.74 (95% CI 1.41–2.15] and 1.54 (95% CI 1.16–2.05) for edentulism | Both periodontitis and edentulism appear to be associated with PC, even after adjusting for common risk factors. | [16] |
| Prospective cohort study | Blood samples from 405 PC & 416 controls | Antibodies against Porphyromonas gingivalis ATCC 53978 | Individuals with high levels of antibodies against Porphyromonas gingivalis ATCC 53978 had higher risk of PC. | [17] |
| Case-control study | 16S rRNA of 30 PHC patients and 25 healthy controls | Microbiome diversity of the tongue coat | The microbiota dysbiosis of the tongue coat in PHC patients was identified. | [18] |
| Cohort study | Cyst fluid and plasma of suspected PCN | Bacterial 16S DNA copy number and IL-1β | Intracystic bacterial 16S DNA copy number and IL-1β protein quantity were significantly higher in IPMN. | [19] |
| Case-control study | Blood samples from 92 PC & 30 gastric cancer & 35 colorectal cancer & 27 controls | IgG antibodies against Hp | Suggested an association between Hp infection and pancreatic cancer. | [20] |
| Case-control study | ·16S rRNA gene of 14 PC & 14 controls | Hp, IL-6 and CRP | PC patients had higher IL-6 and CRP in blood and a higher incidence of Hp in duodenum | [21] |
| ·Blood samples | ||||
| ·Urea breath test | ||||
| Meta-analysis | Blood samples of 580 PC & 626 controls | Hp and CagA | The evidence of CagA strain-specific associations is respective. | [22] |
| Meta-analysis | 117 meta-analytical or pooled reports of the association between specific risk factors and PC risk. | Hp has estimated population attributable fractions is 4–25%. | Hp infection is the major risk factors associated with PC. | [23] |
| Meta-analysis | 1003 PC & 1754 controls in 8 case-control studies | OR = 1.45 (95% CI: 1.09–1.92) between Hp and PC under the random effects model. | Hp infection can significantly increase the risk of developing pancreatic cancer. | [24] |
| Meta-analysis | 2335 patients in 6 studies | AOR = 1.38 (95%CI: 1.08–1.75; P = 0.009) between Hp and PC | A significant association between Hp seropositivity and development of pancreatic cancer was seen | [25] |
| Meta-analysis | 1083 PC & 1950 controls in 9 studies | OR = 1.47 (95%CI: 1.22–1.77) between Hp and PC | H. pylori infection is significantly, albeit weakly, associated with pancreatic cancer development. | [26] |
| Nested case-control study | 104 cases randomly selected subjects among 507 developed PC, 262 cases from 730 controls | Hp and its CagA protein | Helicobacter pylori infection is not associated with development of PC. | [27] |
| Prospective cohort study | 87 PC & 263 controls from residents born from 1921 to 1949 in Malmö, Sweden | Hp | No association between Hp infection and the risk for PC was found. | [28] |
| Meta-analysis | 65,155 observations in 3 cohort studies and 6 nested case-control studies | OR = 1.09(95%CI: 0.81–1.47) | The linkage of PC to Hp infection was not warranted on the whole. | [29] |
| Prospective cohort study | 19,924 participants including 126 PC | Candida | Individuals with Candida-related lesions had a 70 80% excess risk of developing PC. | [30] |
| Population-based cohort study | 34,829 patients from the National Health Insurance system of Taiwan | Candida | The risks of pancreatic cancer was significantly higher in the Candida Infection group. | [31] |
AOR, adjusted odds ratio; CagA, cytotoxin-associated gene-A; CI, confidence interval; CRP, C-reactive protein; HOMIM, Human Oral Microbiological Identification Microarrays; Hp, Helicobacter pylori; IgG, Immunoglobulin G; IL, interleukin; IPMN, intraductal papillary mucinous neoplasm; PC, pancreatic cancer; PCN, pancreatic cystic neoplasm; PHC, pancreatic head carcinoma; Porphyromonas gingivalis ATTC 53978, a pathogenic periodontal bacteria; qPCR, Real-time quantitative polymerase chain reaction; RR, relative risk