Muller and Barrieshi-Nusair (2007) assessed the association of a combination of IL1A-889 and IL1B+3954 alleles on plaque associated gingivitis among 50 affected non-smoking Arabs (34 females) between the ages of 18 and 28-years. Reverse hybridization showed that 52% of the sample population was genotype-positive, thus, carrying both alleles. Upon periodontal probing, these genotype-positive subjects were found to have significantly fewer bleeding sites. In a two-level, repeated measures model, adjusted for gender, probing depth, plaque index, and calculus proportion, the IL-1 genotype was the only factor that remained significant.

Al-Moundhri et al. (2006) were the first to study the association of IL-1B and IL-1RN gene polymorphism with gastric cancer risk in an Omani population of 118 patients (mean age of 56.5 years, males 55.1%) diagnosed with gastric cancer in the period of 2002 to 2005. A group of 245 healthy individuals (mean age of 29.3 years, 56.9% males) from the same ethnic group and geographical region as the patients, were chosen as control. The genotyping of IL-1B -31, -511, and +3954 polymorphism was carried out by using Flourogenic 5-nuclease assay. For the VNTR polymorphism of IL-1RN, the 86-bp tandem repeat region in intron 2 of IL-1RN was amplified by PCR. In all the patients and 89 controls, the Helicobacter pylori status was determined by ELISA for H. pylori immunoglobulin G (IgG) antibody. In the controls, the distribution of IL-B1 and IL-1RN alleles did not deviate much from that expected in the Hardy-Weinberg equilibrium. IL-B1 -31 allele had a frequency in the Omani population of 48% when compared to 34% and 51% in the Caucasian and Asian populations. This study showed linkage disequilibrium between IL-B1 -31 T-to-C and IL-B1 -511 C-to-T in Omani patients and controls. The study showed an increased gastric risk associated with combined genotype of the IL-1RN *2/L with the homozygous wild IL-1B -31 TT, the combined genotype of IL-1RN *2 with IL-1B -31 *C allele carrier (twofold increase), and IL-1RN *2 in combination with homozygous wild IL-1B +3954 CC, or with IL-1B +3954 *T allele carrier (three fold increase). Almost 57% of the patients and 60% of the controls were positive for H. pylori and the risk of gastric cancer was still absent in IL-1B -31 and +3954. Upon classification of the gastric cancer according to histology as intestinal or non-intestinal, no effect on the gastric cancer risk for any of the genotypes was evident. Al-Moundhri et al. (2006) proved the ethnic differences in the effect of IL-1B polymorphism on gastric cancer carcinogenesis due to the absence of association between the IL-1B alleles (-31 and -511) and gastric cancer, but their results on the association between gastric cancer and IL-1RN polymorphism were consistent with previous reports.

Snoussi et al. (2005) investigated the potential association of the polymorphism of interleukin 1-beta (IL1B) with the susceptibility, clinicopathological characteristics, and prognosis of breast carcinoma. The study included 200 unrelated control subjects (191 females and nine males) and 305 unrelated patients with breast carcinoma (301 females and four males). At the time of analysis, 65 patients experienced recurrence and 18 patients among them died from breast carcinoma (27.7%). Genomic DNA was extracted from peripheral blood leukocytes by a salting procedure. By performing polymorphism analysis of the IL1B gene, it was found that the frequency of the IL1B (+3954) TT homozygous genotype had a higher rate in the patients group than in the controls, but the difference reached only borderline significance. The T (+3954) allele of the IL1B gene was observed to be highly associated with the aggressive forms of breast carcinoma. That was due to its presence in 63.75% of patients with large tumors (T3-T4), in 66.66% of patients having tumors with high SBR tumor grade, and in 61.11% of patients with lymph node metastasis. A remarkably strong association between disease-free survival (DFS) rate and IL1B (+3954) TT genotype was found in all 305 patients. The estimated 3-year DFS rate in the group of patients with IL1B (+3954) TT genotype was 79.4%. Snoussi et al. (2005) suggested that the genetic variations in IL1B were likely to play an important role in the genetic predisposition to breast carcinoma.