While regulatory T cells (Tregs) are a poor prognostic factor for lung cancer, they may be detected as Forkhead box P3+ (FOXP3+) and cluster of differentiation (-CD) 4+ T cells by classifying FOXP3+CD4+ T cells into different subpopulations of CD4 cells.
To classify clusters of tumor-infiltrating Tregs in lung adenocarcinoma based on the mRNA expression levels of interleukin-12 subunit alpha (IL12A) and transforming growth factor beta 1 (TGFB1) in tumor specimens.
Seventy-nine patients with lung adenocarcinoma were evaluated in this study. Clinical data were obtained from the patients’ medical records, while tumor tissue samples were preserved as formalin-fixed paraffin-embedded (FFPE) tissue specimens. Immunohistochemical staining for CD4, CD8 and FOXP3 was performed and stained cell counts were obtained under 5 high-power fields. cDNA was synthesized from total RNA extracted from FFPE tissue specimens and amplified with Taqman probes for FOXP3, IL12A, TGFB1, and the glyceraldehyde-3-phosphate dehydrogenase gene.
Two clusters were identified: IL12AlowTGFB1low (Cluster 1: n = 44) and IL12AhighTGFB1high (Cluster 2: n = 39). Although no significant difference in the FOXP3+ cell/CD4+ cell ratio was observed between the 2 clusters (p = 0.921), the high FOXP3+/CD4+ cell ratio group showed a significantly poorer relapse-free survival rate than the low FOXP3+/CD4+ cell ratio group in Cluster 1 (p = 0.031).
Although the results revealed no direct association between Tregs and prognosis according to each subtype, these results suggest that if a lung cancer specimen contains low levels of IL12A and TGFB1, the FOXP3+/CD4+ cell ratio is useful for predicting the prognosis of lung cancer.
About The Expert
Hiroyasu Matsuoka
Hirochika Matsubara
Aya Sugimura
Tsuyoshi Uchida
Tamo Kunimitsu
Tomofumi Ichihara
Yuichiro Oonuki
Yoshihiro Miyauchi
Tetsuo Kondo
Hiroyuki Nakajima
References
PubMed