Endometriosis is a common chronic disease, affecting women of reproductive 
age. Typical symptoms include severe menstrual pain, other pelvic pain symptoms 
as well as infertility. Adolescent onset of symptoms is common, and the 
delay between the onset of symptoms and the diagnosis is typically several years. 
Presently, the diagnosis can be confirmed only by laparoscopy. The symptoms 
can be alleviated with hormonal medications or surgery, but there is no curable 
treatment. 
This study aimed to evaluate the prevalence of symptoms suggestive of endometriosis 
among adolescent girls. Furthermore, the value of a panel of 29 serum cytokines 
in the diagnosis of endometriosis, the usefulness of serum HE4 (Human 
Epididymis Secretory Protein 4), a novel biomarker for ovarian cancer, in discriminating 
ovarian endometriotic cysts from ovarian cancer, as well as the longterm 
effects of surgery on pain were assessed. These studies were based on two 
prospective cohorts: The ENDOMET study, including 137 endometriosis patients 
scheduled for surgery and 62 healthy women, and the TEENMAPS questionnaire 
study that included 1103 adolescent girls aged 15–19 years. 
The study showed that dysmenorrhea was prevalent among teenagers, while other 
pain symptoms were less common. Importantly, approximately 5–10% of adolescent 
girls had symptoms suggestive of endometriosis. Among the potential 
diagnostic markers, the serum concentrations of five cytokines were significantly 
different between endometriosis patients and healthy controls, but these markers 
did no significantly improve the diagnostic accuracy of that obtained with the 
biomarker CA-125 alone. Interestingly, serum levels of HE4 were not increased 
in endometriosis, and thus, this biomarker is useful in differentiating ovarian endometriosis 
from ovarian cancer. Surgery was found to result in significant longterm 
alleviation of pain during 5-year follow-up, and women with deep infiltrating 
endometriosis benefitted the most.