Conflicting opinions exist concerning clinical and pathological presentation, as well as evolution and prognosis, of breast cancer in young women. The roles of associated pregnancy and lactation on these parameters is also unclear. These two conditions are studied in the present work through the comparison of two breast cancer patient age groups: patients under the age of 30 (Group A) and premenopausal patients aged 45-49 (Group B). Rapidly growing and/or inflammatory breast cancer (rapidly progressing breast cancer: RPBC)--a special form of Breast Cancer with a poor prognosis very frequent in the Tunisian breast cancer population--was more often present among Group A patients. This difference is a consequence of the more frequent association of this breast cancer group with pregnancy or lactation; nearly all the cases of breast cancer associated with pregnancy or lactation are RPBC. For breast cancer without the pregnancy/lactation association, the younger group generally shows poorer histological grading and more severe evolution. The number of patients in our study is not really sufficient to allow statistically significant conclusions, but it does seem clear that young age and associated pregnancy/lactation are aggravating factors in Tunisian breast cancer patients.

Variable association of transforming growth factor beta 1 (TGFβ1) in breast cancer (BC) pathogenesis was documented, and the contribution of specific TGFB1 polymorphisms to the progression of BC and associated features remains poorly understood. We investigated the contribution of TGFB1 rs1800469, rs1800470, rs1800471, and rs1800472 variants and 4-locus TGFB1 haplotypes on BC susceptibility, and pathological presentation of BC subtypes. Study subjects comprised 430 female BC cases, and 498 cancer-free control women. BC-associated pathological parameters were also evaluated for correlation with TGFB1 variants. Results obtained showed that the minor allele frequency (MAF) of rs1800471 (+74G>C) was higher seen in BC cases than in control subjects, and was associated with increased risk of BC. Significant differences in rs1800471 and rs1800469 (−509C>T) genotype distribution were noted between BC cases and controls, which persisted after controlling for key covariates. TGFB1 rs1800472 was positively, while rs1800470 was negatively associated with triple negativity, while rs1800470 positively correlated with menarche, but negatively with tumor size and molecular type, and rs1800469 correlated positively with menstrual irregularity, distant metastasis, nodal status, and hormonotherapy. Heterogeneity in LD pattern was noted between the tested TGFB1 variants. Four-locus (rs1800472-rs1800471-rs1800470-rs1800469) Haploview analysis identified haplotype TGCT to be negatively associated, and haplotypes CGTT and CCCC to be positively associated with BC. This association of CGTT and CCCC, but not TGCT, with BC remained significant after controlling for key covariates. In conclusion, TGFB1 alleles and specific genotypes, and 4-locus TGFB1 haplotypes influence BC susceptibility, suggesting dual association imparted by specific SNP, consistent with dual role for TGFB1 in BC pathogenesis.