A new protein to predict outcomes in small cell lung cancer?

The article evaluated the accuracy of YKL-40 levels to predict a patient’s response to chemotherapy for the treatment of SCLC and their cancer outcomes.

Small cell lung cancer (SCLC) accounts for 15% of all lung cancers and has a low 5-year survival rate of 10-26% due to relapse (cancer returns).

Biomarkers (a measurable indicator of a disease condition) play a key role in disease management. One such biomarker, YLK-40 (a protein made only by cancer cells), appears to be able to predict both the patients’ chance of survival and response to chemotherapy (drugs used to treat cancer) in certain cancers. This can help to make sure the patient receives the treatment that will give them the best chances of survival.

The authors aimed to evaluate whether YLK-40 could predict outcomes in SCLC. 120 patients with SCLC were chosen for this study. 40 healthy volunteers were used as controls to compare outcomes. Patients received maximum 6 chemotherapy cycles (cisplatin [Paraplatin] and etoposide [Etopophos] or irinotecan [Camptosar]). The average follow-up was 14 months. High YLK-40 levels were determined to be those >65.7 ng/mL.

YLK-40 levels in SCLC patients (average 72 ng/ml) were higher than in control participants (average 48 ng/ml) before chemotherapy. Those with extensive disease (cancer has spread beyond the side of the chest that it originated in) also had significantly higher levels than those with limited disease (cancer is only present in the side of the chest that it originated in).

Of those with high levels of YLK-40 before chemotherapy, 47% achieved a complete (total disappearance of signs and symptoms of cancer) or partial response (some disappearance) to the treatment. Of those with low levels of YLK-40 before chemotherapy, 69% achieved complete or partial response to treatment. The levels of YLK-40 in patients who responded were significantly lower than those who didn’t respond to chemotherapy.

A high YLK-40 level was shown to be an independent method of predicting patient survival. For those with high levels, the average overall survival was 10 months while the average time between treatment and disease progression was 6 months. For those with low levels, the average overall survival was 18 months while the average time between treatment and disease progression was 9 months.

The study concluded that YKL-40 levels can predict cancer stage, responsiveness to chemotherapy and patient outcome.

There was a clear sex disparity (95 males compared to 25 females) so the next study should have a larger pool of patients with a more equal gender balance.