FCPS Part 1 Pathology MCQs by Subject: Biochemistry, Neoplasia & Pharmacology

Sample FCPS Part 1 Pathology MCQs from three subjects candidates tend to under-revise — Biochemistry, Neoplasia and Pharmacology — each with the correct answer explained.

Beyond histopathology and haematology, FCPS Part 1 Pathology draws a meaningful share of questions from biochemistry, neoplasia and pharmacology — subjects candidates often under-revise because they assume Pathology means tissue slides. Below is a sample across all three.

Biochemistry & Molecular Biology

1. Phenylketonuria (PKU) results from a deficiency of which enzyme?

A) Tyrosinase
B) Phenylalanine hydroxylase ✅
C) Homogentisate oxidase
D) Branched-chain ketoacid dehydrogenase

Without this enzyme, phenylalanine cannot convert to tyrosine and accumulates, causing intellectual disability if untreated; newborn screening programmes test for exactly this.

2. Statins lower cholesterol by inhibiting which rate-limiting enzyme?

A) Acetyl-CoA carboxylase
B) HMG-CoA reductase ✅
C) Lipoprotein lipase
D) Cholesterol esterase

HMG-CoA reductase controls the rate-limiting step of hepatic cholesterol synthesis, which is why inhibiting it is the single most effective way to lower LDL pharmacologically.

Neoplasia

3. The tumour marker CA-125 is most closely associated with which malignancy?

A) Ovarian carcinoma ✅
B) Colorectal carcinoma
C) Hepatocellular carcinoma
D) Prostate carcinoma

CA-125 is used to monitor treatment response and detect recurrence in ovarian cancer, though it can also rise in benign conditions like endometriosis.

4. The most common benign neoplasm of the uterus is:

A) Endometrial polyp
B) Leiomyoma ✅
C) Adenomyosis focus
D) Leiomyosarcoma

Leiomyomas (fibroids) are smooth-muscle tumours found in a large proportion of women by their forties; malignant transformation to leiomyosarcoma is rare.

Pharmacology

5. Rapid infusion of which antibiotic classically causes flushing and hypotension known as "red man syndrome"?

A) Gentamicin
B) Vancomycin ✅
C) Ceftriaxone
D) Ciprofloxacin

This is a direct histamine-release reaction to rapid infusion, not a true allergy, and it is managed by slowing the infusion rate and giving antihistamines.

6. Long-term use of which anticonvulsant classically causes gingival hyperplasia?

A) Sodium valproate
B) Phenytoin ✅
C) Carbamazepine
D) Levetiracetam

Phenytoin's effect on gingival fibroblasts causes overgrowth in a meaningful minority of long-term users, which is why dental hygiene is emphasised in these patients.

Why These Subjects Still Decide Your Score

It's tempting to spend most of Pathology revision on histology slides and organ-system pathology, and treat biochemistry, neoplasia and pharmacology as settled from earlier years. In HighYield's own Pathology bank, these three subjects together account for a sizeable share of the question pool — enough that skipping them is a measurable risk to your score.

HighYield's FCPS Part 1 Pathology question bank covers every subject in the paper, each question explained. For a broader sample across anatomy, physiology, haematopathology and microbiology, see our FCPS Part 1 Pathology MCQs guide. Try the first 20 questions free, no sign-in required.